The influence of different error estimates in the detection of post-operative cognitive dysfunction using reliable change indices with correction for practice effects.

The reliable change index (RCI) expresses change relative to its associated error, and is useful in the identification of post-operative cognitive dysfunction (POCD). This paper examines four common RCIs that each account for error in different ways. Three rules incorporate a constant correction for practice effects and are contrasted with the standard RCI that had no correction for practice. These rules are applied to 160 patients undergoing coronary artery bypass graft (CABG) surgery who completed neuropsychological assessments preoperatively and 1 week post-operatively using error and reliability data from a comparable healthy non-surgical control group. The rules all identify POCD in a similar proportion of patients, but the use of the within subject standard deviation, expressing the effects of random error, as an error estimate is a theoretically appropriate denominator when a constant error correction, removing the effects of systematic error, is deducted from the numerator in a RCI.     

Health experiences and employment status in subjects with chronic back pain: a long-term perspective.

The purpose of this study was to describe health experiences, focused on gender and return to work, in subjects with chronic low back pain in a long-term perspective. The convenient sample consisted of 12 subjects who had attended a pain rehabilitation program 6 years earlier. Typed interviews were transcribed, and a content analysis approach was used. Five categories were found: coping, root causes, control/influence, pain, and sleep. The interviews showed that the subjects expressed well-being, although pain had become part of their daily life. However, both gender and well-being group differences were identified. The women and the group with reduced well-being used the root causes category in a higher degree than the men and the well-being group did. The conclusion is that there are differences according to both gender and return to work within the subjects with chronic pain and that these differences are related to both root causes and coping pattern.     

Dioxin concentrations in the blood of workers at municipal waste incinerators.

OBJECTIVES--Increased concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) in pooled blood samples from workers at municipal waste incinerators have been reported. This study was undertaken to confirm these results in individual blood samples from potentially exposed and unexposed workers at municipal waste incinerators compared with matched unexposed controls and compared with concentrations in the slag and fly ash from the municipal waste incinerators. METHODS--Concentrations of PCDDs and PCDFs were determined in the blood of 10 workers from an old municipal waste incinerator without adequate pollution controls, 11 workers from a newer incinerator with modern pollution controls, and 25 controls from the general population group matched for age (+/- 10 years), sex, and race, and in the slag and fly ash from the older incinerator. RESULTS--Significant increases of certain PCDDs and PCDFs were found in the blood of the workers from the older incinerator compared with the controls as follows: octaCDD (1051 (438) v 637 (344), P < 0.001), hexaCDF (52.3 (28.7) v 30.2 (18.2), P < 0.01), heptaCDF (43.9 (30.4) v 22.7 (12.4), P < 0.001), total PCDDs (1262 (484) v 825 (454), P < 0.001), total PCDFs (133.0 (68.1) v 93.7 (36.7), P < 0.05), and total PCDD/Fs (1395 (537) v 918 (437), P < 0.001). The workers from the older incinerator with the greatest exposure were found to have the most significant increases of the blood PCDDs and PCDFs, and the pattern of increased PCDD and PCDF congeners in the blood corresponded to the pattern in the incinerator slag and ash. No significant differences were found between the blood concentrations of the workers at the newer incinerator and the controls. CONCLUSION--Occupational exposure to slag and fly ash from municipal waste incinerators may increase the blood concentrations of PCDDs and PCDFs. Modern pollution control technology in new incinerators may be able to minimise potential exposure to slag and fly ash and thus the absorption of PCDDs and PCDFs from this source.     

Cyclic AMP levels of C6 glioma cells treated with cis-dichlorodiammine platinum (cis-DDP)

Rat C6 glioma cells were cultured for 3-4 days in MEM supplemented with bovine serum. After 10 min incubation of cells with 0.075, 1.0 or 7.5 micrograms ml-1 cis-DDP the basal cAMP levels (7.87 +/- 0.4 pmoles mg-1 protein) were not affected. In the presence of a phosphodiesterase inhibitor, IBMX, an increase of cAMP occurred; the later was more pronounced in cis-DDP treated cells than in the controls. This suggests that both adenylate cyclase and cAMP-phosphodiesterase were proportionally influenced at this period and that the stimulatory effect of cis-DDP on AC could be demonstrated only when increased activity of PDE had been blocked by IBMX. At later time intervals (10 h-40 h), a 5- to 17-fold elevation of cAMP levels was observed even in the absence of IBMX. Pretreatment of the cells with cis-DDP significantly potentiated cAMP accumulation in response to NE alone and to cis-DDP plus NE could be prevented to a large extent by propranolol; in cis-DDP treated cells the propranolol protection was more effective, both in the absence and the presence of IBMX. The pretreatment of cells with an alpha-blocker, Regitin, did not significantly influence cAMP accumulation. The results indicate that the cis-DDP stimulated cAMP response to NE is mediated via an interaction with beta-adrenergic receptors. The late increase in cAMP content may be a mediator of the morphological changes in these cells following exposure to cis-DDP.     

Hormone replacement therapy dissociates fat mass and bone mass, and tends to reduce weight gain in early postmenopausal women: a randomized controlled 5-year clinical trial of the Danish Osteoporosis Prevention Study.

The aim of this study was to study the influence of hormone replacement therapy (HRT) on weight changes, body composition, and bone mass in early postmenopausal women in a partly randomized comprehensive cohort study design. A total of 2016 women ages 45-58 years from 3 months to 2 years past last menstrual bleeding were included. One thousand were randomly assigned to HRT or no HRT in an open trial, whereas the others were allocated according to their preferences. All were followed for 5 years for body weight, bone mass, and body composition measurements. Body weight increased less over the 5 years in women randomized to HRT (1.94 +/- 4.86 kg) than in women randomized to no HRT (2.57 +/- 4.63, p = 0.046). A similar pattern was seen in the group receiving HRT or not by their own choice. The smaller weight gain in women on HRT was almost entirely caused by a lesser gain in fat. The main determinant of the weight gain was a decline in physical fitness. Women opting for HRT had a significantly lower body weight at inclusion than the other participants, but the results in the self-selected part of the study followed the pattern found in the randomized part. The change in fat mass was the strongest predictor of bone changes in untreated women, whereas the change in lean body mass was the strongest predictor when HRT was given. Body weight increases after the menopause. The gain in weight is related to a decrease in working capacity. HRT is associated with a smaller increase in fat mass after menopause. Fat gain protects against bone loss in untreated women but not in HRT-treated women. The data suggest that women's attitudes to HRT are more positive if they have low body weight, but there is no evidence that the conclusions in this study are skewed by selection bias.     

Effects of postoperative pain on lung volume in patients undergoing aortic surgery

To evaluate the potential advantages of the administration of extradural morphine to control postoperative pain and its effects on respiratory function, 39 patients were randomly assigned to one of two groups before aortic surgery. The first group (20 patients) received intravenous analgesia as required (control group). The second group (19 patients) received extradural morphine in a programmed fashion. During the immediate postoperative period the following parameters were measured in both groups: respiratory rate, vital capacity, peak expiratory volume in the first second, PaO2, PaCO2, arterial pH, heart rate, and systolic and diastolic blood pressure. In the group treated with morphine the postoperative increase in heart and respiratory rate was significantly smaller than in the control group (p less than 0.01). Postoperative forced pulmonary volumes were higher in the morphine group (p less than 0.01). However, there were no differences in time of hospitalization between both groups. There were more complications in the control group, but the difference did not reach statistical significance.     

Structural and histomorphometric studies of iliac crest trabecular and cortical bone in autosomal dominant osteopetrosis: a study of two radiological types

Cylindrical iliac crest biopsies were obtained from 16 patients with autosomal dominant osteopetrosis after intravital double labeling with tetracycline, and compared with normal age- and sex-matched controls. Ten patients had the radiological type I (5 women, 5 men, aged 17-62 years, mean 42) characterized by diffuse, symmetrical osteosclerosis and enlarged thickness of the cranial vault. Six patients had type II (2 women, 4 men, aged 22-44 years, mean 36), where "Rugger Jersey Spine" and endobone are characteristic findings. Structural studies of cortical and trabecular bone were performed, and trabecular bone resorption and formation rates were studied using dynamic histomorphometry. The total biopsy length (C. Wi) were increased in type I (p less than 0.05), and unchanged in type II. Both types showed increased cortical width (Ct. Wi) (p less than 0.01 and p less than 0.05, respectively), and decreased fractional width of cancellous bone (Cn.Wi/C.Wi) (p less than 0.01 and p less than 0.05). The fractional trabecular bone volume (BV/TV) and trabecular thickness (Tb. Th) were both significantly increased in type I (p less than 0.05), while resorptive and formative indices of trabecular bone remodeling were normal. No difference was found in trabecular bone balance, which was slightly positive in both patients and controls. In type II osteopetrosis the eroded surfaces (OS/BS) were significantly increased (p less than 0.01), as was the total resorptive period RP) (p less than 0.05). The resorption depth (R.D.) was normal, while the resorption rate (MRR) was insignificantly decreased. Many big multinucleated osteoclasts were seen in this type suggesting defective resorptive function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Contraction-specific differences in maximal muscle power during stretch-shortening cycle movements in elderly males and females

Elderly people (age 75 years; n=48 males and 34 females) were studied in order to elucidate gender differences in elderly subjects on the determinants of muscle power (force and velocity) during a stretch-shortening cycle. All subjects performed three maximal counter-movement vertical jumps using both legs, on a force platform (Kistler 9281 B). The eccentric (Ep) and concentric (Cp) phases of the jumps were analyzed. The Ep was further divided into an acceleration phase (Ep_acc: from the start of the downward movement to the maximal negative velocity) and deceleration phase (Ep_dec: from the maximal negative velocity to the end of the downward movement). Jump height for the men was higher than for the women (P < 0.001). During both Ep_acc and Ep_dec no significant differences were observed between males and females in force and power generation. However, the men had a higher peak muscle power during the Cp, which may be explained exclusively by the velocity determinant (P < 0.001). No specific gender-related strategy appeared to influence the motor pattern of the movement. The comparable eccentric force generation of the leg extensors in both genders suggests a similar ability to cope with eccentric muscle actions during everyday activities. In contrast, the marked lower capacity for concentric contractions in women may result in an impaired performance, especially in activities where intense and rapid movements are essential, for example when reversing a forward fall. This may be one reason why elderly women are more prone to falls than are elderly men. Accepted: 19 September 2000