Sleep and recovery in physicians on night call: a longitudinal field study

Background  

It is well known that physicians' night-call duty may cause impaired performance and adverse effects on subjective health, but there is limited knowledge about effects on sleep duration and recovery time. In recent years occupational stress and impaired well-being among anaesthesiologists have been frequently reported for in the scientific literature. Given their main focus on handling patients with life-threatening conditions, when on call, one might expect sleep and recovery to be negatively affected by work, especially in this specialist group. The aim of the present study was to examine whether a 16-hour night-call schedule allowed for sufficient recovery in anaesthesiologists compared with other physician specialists handling less life-threatening conditions, when on call.     

Mechanical restitution curves: a possible load independent assessment of contractile function.

OBJECTIVE: The time constant of mechanical restitution (T((MRC))), proposed to reflect changes in calcium release and uptake, has been shown to increase in left ventricular (LV) failure, and might have a potential as an index of contractile function. However, in vivo studies of the effect on T((MRC)) of changing loading conditions in the normal and failing heart have not been reported. Consequently, in this study, we tested the hypothesis that the increase in T((MRC)) in vivo is independent of preload and afterload. METHODS: Left ventricular pressure-volume loops were assessed at baseline in eight open chest pigs using the combined pressure-volume conductance catheter technique during right atrial pacing at 120b/min. Mechanical restitution curves (MRC) were constructed during four different loading conditions in all eight animals: uninfluenced load, reduced preload (balloon catheter in v. cava inferior), increased afterload (balloon catheter in descending aorta), and increased preload combined with reduced afterload (aortocaval shunting). Acute LV failure was then induced by microembolization through the left main coronary artery, and the experimental protocol was repeated. Contractile response was defined as the maximal first derivative of pressure (dP/dt(max)), and T((MRC)) was calculated using a least square approximation algorithm. RESULTS: Hemodynamic data 30min after microembolization showed decreased mean arterial pressure (98+/-14-67+/-10mmHg, (mean+/-SD) P<0.0001) and dP/dt(max) (1482+/-193-1001+/-125mmHg/s, P=0.001). Stroke volume decreased from 30+/-5 to 20+/-5ml (P<0.0001) compared to baseline, and preload recruitable stroke work decreased from 52+/-7 to 31+/-10mmHg (P=0.002). T((MRC)) increased in all eight animals after induction of LV failure at all loading conditions. There was no difference between the different loading conditions at baseline, nor at LV heart failure, but T((MRC)) increased significantly after the induction of heart failure (ANOVA, two ways). CONCLUSIONS: We have shown that the left ventricular T((MRC)) increases after developed heart failure. The increase in T((MRC)) was independent on loading conditions and thus have a potential for a contractility index.     

Hormonal responses to high- and moderate-intensity strength exercise

The hormonal responses of nine male, strength athletes to strength exercise were examined. The athletes performed one moderate- and one high-intensity strength exercise workout. In the high-intensity workout, the load was 100% of each subject's three-repetition maximum (3-RM) for squats and front squats, and 100% of each subject's six-repetition maximum (6-RM) for leg extensions. In the moderate-intensity workout, the load was 70% of the high-intensity protocol. Rest periods between sets were 4–6 min for both workouts. Blood samples were taken before, 30 min into, and every 15 min for the 1st h after exercise, and then 3, 7, 11, 22 and 33 h after exercise, thus allowing examination of both the acute and prolonged hormonal responses. Blood samples were analyzed for testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), cortisol, adrenocorticotrophic hormone (ACTH), growth hormone (GH), insulin-like growth factor (IGF-1), insulin, sex hormone binding globulin, creatine kinase, total protein, glucose and lactate. The acute responses of testosterone and cortisol were greater during the high-intensity protocol as compared to the moderate-intensity protocol. The cortisol response was associated with an increase in ACTH concentration. LH and FSH showed no response to either protocol. Acute GH responses were not different between protocols. There were great inter-individual differences in acute GH responses to both protocols. There were no significant differences between protocols with regard to prolonged responses for any hormone. In both trials, IGF-1 concentrations were significantly lower at 0800 hours the morning after exercise as compared to concentrations found at 0800 hours the morning before exercise. The mechanisms responsible for reducing IGF-1 concentration in these trials are unclear, and it is not known if this reduction observed 22 hours after exercise is of physiological significance. Accepted: 13 December 1999     

Maternal Age at Menarche and Pubertal Timing in Boys and Girls: A Cohort Study From Chongqing,China

PurposeThis study explored the association of maternal age at menarche (AAM) with pubertal timing among girls and boys in Chongqing, China.MethodsPubertal development of 1,237 children (542 girls and 695 boys) were examined half-yearly through inspection and palpation from April 2014 to June 2019. Characteristics of parents and maternal AAM were collected by a parental questionnaire at baseline. Maternal AAM was used both as a continuous and a categorical variable in Cox regression models.ResultsA total of 1,198 children (528 girls and 670 boys) were included in the study. In the simple Cox model, earlier maternal AAM was associated with girls' earlier menarche, breast and pubic hair development, and boys' first ejaculation, testicular development, and genital development. When adjusting for children's body mass index z-scores (BMIz) and socioeconomic covariates, we found that girls whose mothers had early AAM had a higher risk of earlier onset of menarche (hazard ratio [HR]: .922, 95% confidence interval [CI]: .852–.998 for continuous maternal AAM, HR: 1.297, 95% CI: 1.041–1.616 for maternal AAM ≤13 years), and boys whose mother achieved menarche earlier experienced a higher risk of earlier onset of first ejaculation (HR: .896, 95% CI: .830–.968). Children's BMIz were related to all nine pubertal milestones. Parental education and relationship, birth weight, parity, and family type were also associated with pubertal timing.ConclusionsEarlier maternal AAM was related to earlier pubertal timing in both girls and boys in Chongqing, especially girls' age at menarche and boys' first ejaculation. Children's BMIz was the most consistent factor for pubertal timing. Children's BMIz and socioeconomic conditions had greater influence on most pubertal milestones than maternal AAM.     

Lanzoprazole promotes gastric carcinogenesis in rats with duodenogastric reflux

Background Duodenogastric reflux is known to cause an increased frequency of cancer in the glandular portion of the stomach in rats. Furthermore, it is debated whether inhibition of gastric acid secretion may promote gastric carcinogenesis. In the present study we examined the combined effect of gastroduodenal reflux and acid inhibition with respect to the development of gastric carcinoma in the rat.Methods Following the construction of a gastrojejunostomy in male Wistar rats, half of them were given the proton pump inhibitor lanzoprazole for 1 year. The rats were then killed and the pH in the stomach and gastrin in blood were measured. The stomach was examined macroscopically as well as histologically.Results Gastrin levels at autopsy were significantly increased in treated rats compared to the control group, confirming an effect of lanzoprazole on gastric acid secretion. Body weight was significantly reduced in the treated rats. Thirty of 79 rats developed gastric cancer, and they were all adenocarcinomas of the Lauren intestinal type. Gastric cancers occurred significantly more often in lanzoprazole-treated rats (50%) compared with controls (27%).Conclusion Lanzoprazole given orally enhances the carcinogenic effect of duodenogastric reflux in rats.     

USA300 methicillin‐resistant Staphylococcus aureus in Norway

Moen AEF*, Tannæs TM, Leegaard TM. USA300 methicillin‐resistant Staphylococcus aureus (MRSA) in Norway. Community‐associated methicillin‐resistant S. aureus USA300 is known for its ability to disseminate and colonize and the clone has been detected globally. We studied the most populated area in Norway in search for the strain and for signs of endemic establishment. Strain typing techniques such as spa‐, SCCmec‐ and dru‐typing, pulsed‐field gel electrophoresis and detection of USA300 molecular markers, lukS/F‐PV and arcA, were performed. USA300 has been present in the study area since 2003 and has increased in incidence in parallel with the total MRSA incidence. Most USA300 isolates were found in the community, but isolates were also detected in health care institutions.     

A rapid,high‐throughput screening method for carriage of methicillin‐resistant Staphylococcus aureus

Rapid screening of methicillin‐resistant Staphylococcus aureus (MRSA) colonization prior to hospital admittance is important to reduce nosocomial infections and health care costs. Molecular detection of mecA and S. aureus specific target genes has become widely established for this purpose. However, there are still limitations in potential for high‐throughput screening in the methods described. We have compared the time aspects and workload of four different DNA preparation platforms, resulting in an automated and simple MRSA screening method which combines two liquid handling systems and a simple lysis buffer. We have further transferred our in‐house dual real‐time PCR to a fast‐PCR protocol, reducing the time and labour spent on these samples to a minimum.