Blue-Light Photocleavable Protecting Groups Based on Benzothiadiazole Scaffolds.

An unexpected nucleophilic aromatic substitution lead to a novel benzothiadiazole scaffold that bore the functional group pattern associated with benzyl-type photocleavable protecting groups. The new molecules display efficient photochemical release of leaving groups with blue light. The performance of both ortho- and meta-substituted derivatives was probed through both structural manipulation and computational metrics to improve performance.

Vectorcardiographic changes during cardioangiography with iodixanol and ioxaglate.

AIM: To compare the electrophysiological effects of two contrast media (CM), the non-ionic dimer iodixanol and the ionic dimer ioxaglate using computerised dynamic vectorcardiography (VCG) during coronary angiography. METHODS: The study was designed as a double-blind, three-period crossover, randomised comparison between iodixanol (320 mg I/ml) and ioxaglate (320 mg I/ml). Group 1 (HVV) received ioxaglate (H) in the first injection in the left coronary artery (LCA) and iodixanol (V) in the following injections. Group 2 (VHH) received iodixanol in the first injection in LCA and ioxaglate in the following injections. The first three injections in the LCA were subjected to electrocardiographic analysis. RESULTS: For five out of six VCG variables, there was a significant difference in response between iodixanol and ioxaglate. For these five variables, the deviations from baseline were greater in the ioxaglate than in the iodixanol group (P<0.05). The most pronounced effects from ioxaglate were seen on the ST-segment and T-wave. CONCLUSIONS: Iodixanol caused less pronounced electrophysiological changes than ioxaglate, especially during the repolarisation phase. Vectorcardiography is a sensitive and reproducible technique for detecting electrophysiological effects induced by CM.

Iodixanol and iohexol in cardioangiography. A comparative vectorcardiographic study.

PURPOSE: The non-ionic dimeric contrast medium (CM) iodixanol is isotonic with blood through the addition of electrolytes. In this study, we evaluated computerised dynamic vectorcardiography (VCG) as a tool in CM research by comparing the electrophysiological effects of iodixanol with those of the low-osmolar CM iohexol. MATERIAL AND METHODS: A total of 119 patients referred for cardioangiography were included in this double-blind, randomised, parallel comparison of iodixanol (320 mg I/ml) and iohexol (350 mg I/ml). VCG was recorded and different VCG parameters were analysed. General tolerability, safety and radiographic efficacy were also assessed. RESULTS: Iodixanol induced less changes than iohexol in all VCG parameters and the sensation of warmth was significantly milder after iodixanol, but both CM were well tolerated. VCG might be useful in future studies to analyse electrophysiological effects caused by CM.

Evaluation of perceived and self-reported manual forces exerted in occupational materials handling.

The main objective of the study was to evaluate the ability of workers to reproduce simulated manual work forces correctly and to quantify these forces in Newtons (N) by means of self-reports. Fourteen male and 14 female workers participated in the study. Three experiments were carried out. In the first experiment, the ability to reproduce the magnitudes of simulated manual forces occurring in daily work and to estimate these forces in Newtons was tested. A specially designed force-measuring device was used for this purpose. In the second experiment, the subjects estimated the weights of five boxes ranging from 1 to 30 kg. In the third experiment, the subjects were asked to produce five predetermined push and pull forces ranging in magnitude from 10 to 300 N on to the handle of the force-measuring device. The ability to reproduce the magnitudes of manual forces when simulating four familiar work tasks was good (the intraclass correlation coefficients ranged from 0.75 to 0.95). The ability to quantify these forces in Newtons was not as good (the product moment correlation coefficients ranged from 0.21 to 0.69). When the subjects estimated the weights of boxes they underestimated the weights. When they produced predetermined push and pull forces they exerted higher forces than expected when low force levels were requested and lower forces when high force levels were requested. However, the forces were correctly ranked. In summary, simulation of the manual push/pull forces used in familiar work tasks seemed to offer sufficient reproducibility to be worth testing for validity. Self-reports, used without previous training or without known 'reference forces', seemed to be very rough when the aim was to estimate in kg or Newtons. However, the fact that individuals could rank the forces correctly opens a potential for refinement of self-reports as a method for quantifying manual forces in objective terms, e.g. kg or Newtons.

An interview technique for recording work postures in epidemiological studies. Music-Norrtälje Study Group.

BACKGROUND: The aim of the study was to present and evaluate a work-task-oriented interview technique focusing on the placement of the hands relative to the body and assessing per cent time spent in five standard work postures during a working day. METHODS: The reproducibility of estimated time spent in each work posture was tested by the test-retest method in 32 subjects; 16 were interviewed by the same interviewer and 16 were interviewed by another one at the retest. The validity concerning estimated time spent in th five standard work postures was tested in relation to observations in 58 male blue-collar workers. The mean registration (assessment) time was 6 hours and 15 minutes. RESULTS: No evident differences in the reproducibility depending on same or different interviewers at test and retest could be observed. The linear relationship between times estimated by the interview and by observations was high for four of the work postures: 'sitting' (r = 0.86), 'standing with hands above shoulder level' (r = 0.87), 'between shoulder and knuckle level' (r = 0.75), and 'below knuckle level' (r = 0.93). When the work posture 'standing with hands between shoulder and knuckle level' was divided into 'hands fixed' (r = 0.62) and 'hands not fixed' (r = 0.50) the correlations were weak. Current musculoskeletal complaints did not influence the accuracy of the estimations. CONCLUSIONS: The present task-oriented interview technique may be the best available method to estimate these work postures in a way that requires few resources compared to observations and technical measurements.

Addition of sodium to iohexol. A vectorcardiographic study.

The addition of sodium to nonionic contrast media has reduced the incidence of arrhythmias in animal models. The influence on cardiac function and safety of sodium addition to the nonionic contrast medium iohexol (Omnipaque) was studied in a randomized, double-blind trial in patients undergoing cardioangiography. Fifty-nine patients received iohexol 350 mg I/ml with NaCl 28 mmol/l and 58, iohexol only. ECG changes after contrast injections were evaluated with continuous computerized dynamic vectorcardiography (VCG). QRS-vector difference (QRS-vd), which reflects changes in the QRS-complex, was chosen as the main parameter. Both contrast media caused changes in the QRS-complex, but there was no significant difference between the two. No serious arrhythmias were observed. Both contrast media were well tolerated. No beneficial effects from enriching iohexol with sodium were found. VCG was found to be a valuable tool in the study of contrast medium-induced ECG changes.

Variation in upper limb posture and movement during word processing with and without mouse use.

Work postures and movements of the upper limb were analysed for 12 'mouse' operators and 12 'non-mouse' computer operators employed in word-processing work. Measurements were carried out during correction of a given text. 'Mouse' operators spent 64% of the working time with the operative wrist deviating more than 15 degrees towards the ulnar side, while 'non-mouse' operators spent 96% of the time with the corresponding wrist in neutral position towards radial deviation. The rotation in the shoulder was at all times in neutral position towards inward rotation for 'non-mouse' operators, while 'mouse' operators worked 81% of the time with the shoulder rotated outward more than 30 degrees. 'Mouse' operators corrected a longer text during the given time. Our observations showed long periods of strenuous working postures for 'mouse' operators compared to 'non-mouse' operators. We believe that further investigations need to be carried out on the effects of word-processing techniques and to develop ergonomic work station designs for the 'mouse' and other non-keyboard input devices.

Evaluation of two instruments for recording sitting and standing postures and number of foot steps.

The study evaluates two simple instruments that may be used to describe aspects of physical workload in almost any occupation: a pedometer, which measures the number of steps taken by the subject wearing it, and a posimeter, which quantifies the time spent sitting and the number of changes between sitting and a The present data showed that the pedometer registers the correct number of steps at 'ordinary' walking speed independent of type of floor (plastic carpet and stone floor), shoes (wooden shoes and sneakers) and gender. At 'slow' walking (2.4 km/h) a reduced number of steps was recorded. In a field study the median difference between pedometer registration and observation was 6% (range 1-27) of the observed obtained for the five investigated pedometers was 0-15%. The posimeter was found to give a good estimate of the percentage time spent sitting (mean deviation 3%, range 0-15%). The number of changes between sitting and standing was overestimated by the posimeter (median deviation 63% of the observed). Some extreme working postures can be misread by the posimeter.

Torsion of a lung lobe: diagnosis and treatment.

Intraoperative lobar torsion occurred in 4 of about 2000 patients subjected to thoracotomy. Two of the patients died. Early diagnosis and proper management are of great importance to the outcome. Temporary deflation of the diseased lung by using double lumen endobronchial tube is a potential risk. Early progressive lobar opacity without signs of atelectasis on conventional chest radiograph is indicative of this serious complication. Computerized tomography and bronchoscopy are of diagnostic value. Exploratory thoracotomy must be performed without delay. The injured parenchyma should be sacrificed unless the diagnosis is obtained very early. When the injured lobe or lung is rotated back into normal position the airways may be flooded with serosanguinous fluid which promptly has to be removed. If an attempt is made to save the lobe or the lung, tracheostomy for frequent suction of the airways is indicated in order to prevent "spill-over" and dangerous postoperative hypoxia.

Cardioangiographic findings in patients with arrhythmogenic right ventricular dysplasia.

The dimension, contractility, and regional wall motion of the right and left ventricles were scored on the angiograms of 13 patients with arrhythmogenic right ventricular dysplasia. In 10 patients the right ventricle was enlarged, in eight the contractility of the right ventricle was reduced, and in all but one patient there were regional wall motion abnormalities of the right ventricle. The most common abnormality of regional wall motion was mild hypokinesia. There were bulging or dyskinetic areas in seven patients. Regional wall motion abnormalities of the left ventricle were found in five patients, two of whom also had bulging or dyskinetic areas. The reproducibility of right ventricular dimension, contractility, and regional wall motion scores was generally fair but varied unexpectedly both within and between two observers (Kendall's Tau 0.38-0.92). The score values of regional wall motion for some of the segments differed considerably within and between observers. One of the observers consistently gave higher scores than the other. These data suggest that a more objective approach is needed for evaluating angiographic changes in arrhythmogenic right ventricular dysplasia.

Factors that modify the flow response to intracoronary injections.

Coronary sinus flow (CSF) was measured in seven patients with normal coronary arteries (group A) during intracoronary injections of 6 ml arterial blood, 6 ml blood from the coronary sinus, 3 and 6 ml isotonic saline, 3 and 6 ml hypertonic glucose, and 6 ml of a contrast agent (sodium metrizoate). In 10 patients with coronary artery disease (group B), CSF was measured after administration of 6 ml isotonic saline, 6 ml sodium metrizoate, and 6 ml of another contrast medium (iohexol). In group A, arterial blood did not affect CSF, while coronary sinus blood induced a 33% increase. After 6 ml isotonic saline, there was a 35% increase in flow and after hypertonic glucose an increase of 70%. Metrizoate induced a rise in flow of 109%. In group B, the increase in CSF after intracoronary injection of saline, metrizoate, and iohexol was 30%, 83%, and 67%, respectively. Blood from the coronary sinus, in contrast to arterial blood, induced a marked rise in peak flow, suggesting a role for reactive hyperemia secondary to myocardial hypoxia in this response. A similar mechanism might have been operative after injection of isotonic saline, as well as after the hyperosmolar contrast agents. However, additional mechanisms mediated by the high osmotic pressure of these substances, such as induction of the Bezold-Jarisch reflex, which will induce coronary vasodilation, may have played a role. Finally, when hyperosmolar agents are used, the possibility of some direct vasodilating properties of the agents cannot be excluded.

Shrinking pleuritis with atelectasis. Specificity of abnormalities present at conventional radiography of the lung.

Radiographic appearances claimed to be typical of shrinking pleuritis with atelectasis (SPA) were tested by mingling chest films from 6 SPA patients with those from 56 cancer cases. Two radiologists were asked to interpret the films independently, make a diagnosis, and state what abnormalities could be distinguished. No single abnormality or combination of abnormalities was found to be pathognomonic and the wish to diagnose the SPA cases led to misdiagnosis of cancer in one of 56 cases by each radiologist. To prevent underdiagnosis of cancer, further examinations are required. Careful follow-up of SPA cases, if they are not operated upon, is recommended.

Computer aided exercise electrocardiographic testing and coronary arteriography in patients with angina pectoris and with myocardial infarction.

A set of electrocardiographic criteria for the diagnosis of coronary artery disease was evaluated in two different groups of patients examined by computer aided 12 lead exercise electrocardiographic stress testing and coronary arteriography. One group consisted of patients with severe angina pectoris and the other of patients who had suffered a myocardial infarction three years before the study. Angiographically determined categories of patients could be identified with satisfactory precision by the electrocardiographic criteria under test in the patients with angina pectoris but not in those with infarction. A new method of classifying patients on the basis of data from coronary arteriography improved the correlation with ST segment analysis compared with conventional classification.

Sex differences in cardioangiographic findings after myocardial infarction.

The cardioangiographic findings in 50 women 40-54 years of age were compared with those of a series of 69 men with infarction recruited from the same catchment area and investigated according to the same principles. Women less often had left ventricular abnormalities than men; this difference was mainly confined to patients with non-Q wave infarctions. There was no difference in the prevalence of left ventricular abnormalities among women and men with Q wave infarctions. No major sex difference was found in the prevalence of coronary abnormalities. Collaterals were less common in women than in men.

A case of total bilateral spontaneous pneumothorax.

Bilateral spontaneous pneumothorax with almost complete collapse of the lungs in a 29-year-old man is reported. On admission to hospital the patient was in moderate respiratory distress, but the arterial blood gases were normal. Initially he was treated with bilateral tube drainage. Thoracotomy with parietal pleurectomy was later done on the right side to prevent recurrence.

Effects of iohexol and metrizoate on myocardial blood flow and metabolism.

In 10 patients coronary sinus blood flow (CSBF) was measured during and after injection of iohexol and meglumine-Na-Ca metrizoate in the left coronary artery. Oxygen saturation, lactate concentration and hematocrit were determined in the aorta and coronary sinus before and after a second injection of the two contrast media. The increase in CSBF was significantly more marked and sustained after injection of metrizoate than after iohexol and myocardial arterio-venous oxygen difference was significantly lower. Myocardial oxygen consumption and lactate metabolism were not adversely affected by any of the contrast media. The fall in hematocrit in coronary sinus blood was significantly greater after metrizoate.