The long‐term impact of severe acute respiratory syndrome on pulmonary function,exercise capacity and health status

Background and objective: Severe acute respiratory syndrome (SARS) emerged in 2003 and its long‐term sequelae remain largely unclear. This study examined the long‐term outcome of pulmonary function, exercise capacity, health and work status among SARS survivors. Methods: A prospective cohort study of SARS patients at the Prince of Wales Hospital, Hong Kong was conducted, with serial assessments of lung function, 6MWD and 36 item Short Form General Health Survey at 3, 6, 12, 18 and 24 months after disease onset. The work status was also recorded. Results: Serial assessments were completed by 55 of the 123 (39.9%) subjects, of whom 27 were health‐care workers (HCW). The mean age of the group was 44.4 (SD 13.2) years and 19 (34.5%) were males. At 24 months, 10 (18.2%), 9 (16.4%), 6 (10.9%) and 29 (52.7%) subjects had FEV₁, FVC, TLC and DL_CO < 80% of predicted values, respectively. The mean (SD) 6MWD increased significantly from 439.0 (89.1) m at 3 months to 460.1 (102.8) m at 6 months (P 0.016) and became steady after 6 months. However, 6MWD and 36 item Short Form General Health Survey scores were lower than the normal population throughout the study. Moreover, 29.6% of HCW and 7.1% of non‐HCW had not returned to work 2 years after illness onset. Conclusions: This 2‐year study of a selected population of SARS survivors, showed significant impairment of DL_CO, exercise capacity and health status persisted, with a more marked adverse impact among HCW.     

Effects of dietary factors on antioxidant enzymes in rats exposed to hyperbaric oxygen

To delineate the effect of dietary supplementation with vitamin E (Vit E) alone or in combination with riboflavin (Rib) or selenium (Se) or both, on biological oxidative damage in rat brain and lungs we exposed rats to hyperbaric oxygen (HBO) and measured the activities of glutathione reductase (GSSG-R), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and glucose-6-phosphate dehydrogenase (G-6-PD) prior to or 48 h after exposure. Rats fed the dietary supplements, and a control group maintained on an unsupplemented diet, for 30 d, were each divided into 2 subgroups, of which 1 was exposed to 4.5 absolute atmospheres (ATA) of 100% oxygen for 30 min, hereafter referred to as "exposed". The remaining subgroups were left unexposed. Pre-exposure GSSG-R activity in brain was elevated in all experimentally fed groups (ranging from 23 to 84%) compared with the unexposed control, whereas GSH-Px, G-6-PD and SOD activities were unchanged. The lungs showed significant increases in pre-exposure GSSG-R, ranging from 15 to 28%, and GSH-Px, ranging from 13 to 23%, activities in all the groups fed the supplemental nutrients, except those on Vit E alone. Increases in G-6-PD activity were observed only in those fed supplements of Rib. In most cases exposure to oxygen caused an increase in GSSG-R, GSH-Px and G-6-PD activities. However the increases were higher in the supplemented groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

A Review of Implantable Sensors

Les capteurs biologiques en cours de developpement offrent: bonne performance, petite taille, cout réduit et compatibilité avec des circuits integrés, Ľétal actuel de ces capteurs en ce qui concerne le milieu biologique est presenlé, Des capleurs physiques peuvent mésurer la pression, les débits, ľaccéleration etc. Des capteurs chimiques peuvent mesurer les ions H+, K+, Na+, etc. La recherche nécessaire pour ľimplantalion chez ľhomme est envisagée.
Solid state sensors offer high performance, small size, lower cost, and compatibility with computing circuits. The current status of these sensors for biomedi-cal applications is reviewed. Physical transducers may be used to measure pressure, flow, acceleration, velocity, etc. Chemical transducers may measure H+, K+, Na+, etc. Research required for their implantation is suggested.     

Clinical, Electrophysiological Characteristics, and Radiofrequency Catheter Ablation of Atrial Tachycardia Near the Apex of Koch's Triangle

Atrial tachycardia, with its focus near the apex of Koch's triangle, may carry a potential risk of atrioventricular block during radiofrequency catheter ablation. The efficacy and safety of this procedure have never been addressed. The characteristics and catheter ablation results are reported for six patients with atrial tachycardia near the apex of Koch's triangle. All six patients were female aged 49.6 ± 9.3 years (range 39–63). Organic heart disease was present in 3 (50%) of the 6 patients. The P wave in surface ECG had a mean axis of − 28° (range − 90°–+ 30°) in the frontal plane. The catheter ablation was guided by activation sequence mapping. The energy was titrated from low power level. Atrial overdrive pacing was used to monitor the atrioventricular conduction should accelerated functional rhythm occur. At the final successful ablation site, the local atrial activation was 41.8 ± 9.1 ms before the P wave and His-bundle potential was present in 5 of the 6 patients. All patients had their atrial tachycardia eliminated without recurrence or heart block during a follow-up period of 17.7 ± 8.5 months (range 6–30). In conclusion, atrial tachycardia near the apex of Koch's triangle has distinct clinical and electrophysiological features, Radiofrequency catheter ablation can be performed effectively. However, extreme care must be taken to prevent inadvertent atrioventricular block. Titrated energy application and continuous monitoring of atrioventricular conduction are mandatory.     

The influence of mercury on the secretion of human chorionic gonadotropin in superfused young placental tissue.

The effect of mercury (Hg), as HgCl2, in levels ranging from 0.75 to 12 micrograms/ml medium, on the secretion of human chorionic gonadotropin (hCG) was examined in first-trimester placental explants, after 6 or 24 hr incubation, employing both static and dynamic systems (the latter by superfusion). Later the unbound Hg was washed for 45 min. with fresh medium devoid of Hg, followed by superfusion with the latter medium for 75 min., during which time samples were collected for hCG assay. For the superfusion experiments the parameters used for evaluating the hCG secretion pattern were: mean peak amplitude, pulse frequency and the area under the hCG secretion curve (AUC). The results observed after 24 hr incubation indicate that in the dynamic system the hCG secretion increased significantly, and this increase was dose-dependent. There was also a dose-related increase in mean total hCG secreted by the explants exposed to Hg. Maximal hCG secretion was observed after 24 hr exposure of explants to 6 micrograms of the metal/ml. Both the mean peak amplitude and AUC parameters showed a statistically-significant increase for this dose level. At 12 micrograms/ml, the pulsatile secretion of hCG decreased, but the value for the mean hCG secretion was still higher than that observed for 0.75 and 3 micrograms/ml. After 6 hr incubation, however, there were no significant changes from the control, as judged by all of the above parameters. The levels of hCG secreted by the explants into the media in the static system were not significantly different from their respective controls, for both incubation periods and Hg levels.(ABSTRACT TRUNCATED AT 250 WORDS)