Sympathetic nervous system as transmitter of mechanical loading in bone

Sympathetic innervation has been demonstrated in bone. Adrenergic stimulation is one of the transmitters of bone loss by uncoupling between decreased bone formation and increased bone resorption.

OBJECTIVE

By using a non-specific antagonist of -adrenergic pathway (propranolol per os), we hypothesized that we could rescue the uncoupling induced mechanical unloading bone loss in the rat model of tail-suspension.

MATERIALS AND METHODS

Twenty-two female Wistar rats, 12 week-old, have been divided into three groups: eight tail-suspended rats (SR), six tail-suspended rats treated by propranolol (SRP) and eight non-suspended rats (NSR) during 30 days. Bone mineral density (BMD, g/cm2) has been measured by DXA (Hologic QDR-4500A) at D0 and D30 of the study, in the distal femoral metaphysis (DFM), the femoral diaphysis (FD), the whole body (WB, g) and body composition.

RESULTS

Between D0 and D30, in DFM a significant variation in BMD is observed between NSR and SR (% BMD change: NSR +15.6 +/- 3.1% vs SR -1.0 +/- 1.4%, P < 0.0001) and BMD rescue in SRP group (% BMD change SRP +5.3 +/- 1.5% vs SR -1.0 +/- 1.4%, P = 0.03). In FD, gain of BMD is significant in NSR compared to SR (+17.5 +/- 1.5% vs +8.2 +/- 2.8%, P = 0.007) and to SRP (+17.5 +/- 1.5% vs +10.1 +/- 2.4%, P = 0.046). Gain in SRP group is not significant compared to SR group (P = 0.6). In WB, SRP gain more BMD than NSR (+14.0 +/- 1.8% vs +5.4 +/- 0.7%, P = 0.0002) and than SR (+14.0 +/- 1.8% vs +7.8 +/- 1.4%, P = 0.0043). There is no difference between NSR and SR groups (P = 0.19).

CONCLUSION

We demonstrate that -adrenergic pathway of sympathetic nervous system is a major transmitter pathway of mechanical loading in rat bone. A specific study is necessary to analyse a possible systemic effect of propranolol in rat bone. Propranolol could be used to prevent the induced mechanical unloading bone loss as weightlessness

Asbestos bodies in the sputum of asbestos workers: correlation with occupational exposure

A cross-sectional medical survey including collection of three consecutive sputum samples was carried out among 270 retired workers of a textile and friction materials factory, in order to investigate the relationship between asbestos body identification and asbestos exposure. The individual cumulative asbestos exposure, determined by means of a plant-specific job-exposure matrix based on asbestos air measurements in the workshops, proved to be heavy with a mean cumulative exposure of 217 fibres x mL(-1) x yr. Macrophages and asbestos bodies were identified in sputum samples by light microscopy. The lung origin of the sputum, suggested by the presence of macrophages and/or asbestos bodies, was confirmed in 82.6% of subjects, and 53% of these samples were positive for asbestos bodies. The prevalence of asbestos bodies was not related to sex, smoking status or latency. Conversely, multivariate analysis showed a positive relationship with cumulative exposure, duration and intensity of exposure to asbestos, as well as age and time since retirement. These findings suggest that sputum analysis for asbestos bodies may remain a relevant and noninvasive marker of heavy occupational exposure to asbestos, even years after retirement. Owing to the new perspectives in lung cancer screening, it might contribute to the identification of high-risk subjects.

Role of anxiety and depression in the onset of spontaneous preterm labor

The aim of this cohort study conducted in France in 1997-1998 was to investigate the effects of antenatal anxiety and depression on spontaneous preterm labor. A consecutive series of 634 pregnant women with singleton pregnancies was included. Anxiety and depression were assessed using self-administered questionnaires: Spielberger's State-Trait Anxiety Inventory and the Edinburgh depression scale. Depression scores were dichotomized with a cutoff value suggestive of major depression. The 75th percentile was used for anxiety scores. A logistic regression analysis, controlling for sociodemographic and biomedical factors and including interaction terms, revealed that depression was positively associated with the outcome among underweight women, defined as women with a prepregnancy body mass index below 19 (adjusted odds ratio (OR) = 6.9, 95% confidence interval (CI): 1.8, 26.2). A similar result was observed for trait anxiety in women with a history of preterm labor (adjusted OR = 4.8, 95% CI: 1.1, 20.4). The association was close to significance for state anxiety in women with vaginal bleeding (adjusted OR = 3.6, 95% CI: 0.9, 14.7). These findings show that anxiety and depression, when combined with specific biomedical factors, are associated with spontaneous preterm labor. A synergic action of psychological and biomedical factors on the secretion of placental corticotropin-releasing factor is hypothesized.

[Predictive value of non-automated spermatic parameters and automated kinetic parameters on cleavage rate in fertilization in vitro]

The aim of this work was to determine retrospectively in 114 couples the predictive value of semen analysis for the in vitro fertilization (IVF) outcome when sperm evaluation before IVF was assessed by either conventional parameters or a Hamilton-Thorne automated motility analyser. A backward logistic regression analysis was used to study the relative contribution of each conventional or computerized parameter. Computerized sperm values were the worst index for predicting oocyte fertilization. However a tight relationship between morphology and cleavage ratio was observed. Using ROC analysis, under a 18% threshold, cleavage failure was noted in 71% of couples undergoing an IVF program. This study indicates that morphology is the best parameter for predicting cleavage failure.

Nonspecific back pain in children. A search for associated factors in 14-year-old schoolchildren

BACKGROUND

Nonspecific back pain in children is nearly as common as in adults but is associated with a number of age-specific risk factors including female gender, a family history of low back pain, a high level of physical activity, and prolonged sitting.

OBJECTIVE

To investigate potential school-related risk factors for back pain in children, most notably schoolbag weight expressed as a percentage of body weight (relative schoolbag weight), whether the schoolbag is carried by hand or by a shoulder harness, how the child travels to and from school, and sitting positions.

PATIENTS AND METHODS

123 eighth-graders, 58 girls and 65 boys, with a mean age of 14 +/- 0.6 years, completed an anonymous self-questionnaire during a school day involving six hours of classes. Their schoolbag was weighed on the same day.

RESULTS

Most respondents traveled to and from school in a vehicle (70%), made one trip in each direction each day (75%), and carried their schoolbag by the shoulder harness (92%). The prevalence of back pain on the study day was 27.6%, whereas the cumulative prevalence for the last 12 months was 82.9% with 16.3% of respondents reporting a single episode of pain, 57.7% recurrent pain, and 8.9% chronic pain. A need for a physician visit for back pain was reported in 18.7% of cases, and 14.6% of respondents had missed school and/or sporting activities because of back pain. Female gender was associated with current back pain (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.2-6.1). A relative schoolbag weight of 20% or more was associated with a history of back pain (OR, 3.1; 95% CI, 1.0-9.2), and this effect was larger in children who traveled to and from school on foot and in those who carried their schoolbag in their hand. Sitting on the edge of the chair while completing the questionnaire was significantly associated with a history of a physician visit for back pain (OR, 3.1; 95% CI, 1.0-9.5). Neither handedness nor the position of the questionnaire on the table were significantly associated with back pain in our study population.

CONCLUSIONS

The findings from this cross-sectional study indicate a need for a longitudinal prospective study designed to identify etiologic and prognostic factors of back pain in adolescents, with the goal of devising preventive strategies likely to reduce the risk of low back pain in adulthood.

[Discrepancies between the results of phlebography and Doppler ultrasonography in the diagnosis of asymptotic venous thrombosis after total hip prosthesis. False negatives of phlebography or false positives of Doppler ultrasonography]

OBJECTIVES

Assess the diagnostic performance of phlebography and discrepancies with duplex ultrasonography in screening for asymptomatic deep vein thrombosis after total hip arthroplasty. Search for arguments which would favor contributing false-negatives or false-positives to one of the two exploration methods.

PATIENTS AND METHODS

The study included 24 patients who underwent the 2 explorations independently between day 7 and day 14 in a multicentric therapeutic trial of a new heparin. Discrepancies between the two techniques were recorded. Diagnostic performance of phlebography was calculated from contingency tables. The phlebograms were then reviewed with knowledge of the duplex ultrasonographic findings. The course of the venous thrombus after treatment was monitored with duplex ultrasonography.

RESULTS

Phlebography allowed the diagnosis of thrombus formation in 9 patients. Ultrasonography provided the diagnosis in 14 cases out of 24. Sensitivity of phlebography compared with duplex ultrasonography was 64% (95% CI = 35.1-87.2) (9/14) and specificity was 100% (95% CI = 69.1-100) (10/10). Several localizations were not visualized with phlebography: 3 partially obstructive thrombi near the femoral junction, and 38 distal thrombi including 31 soleus thrombi (fig. 5). When the phlebograms were reviewed again, defects compatible with a partial thrombus were found for the 3 proximal localizations and for 2 of the distal localizations (fig. 1, 2, 4). None of the soleus localizations were visualized. Duplex ultrasonographic follow-up concerned 12 of the 14 patients with a thrombus identified by duplex ultrasonography involving 44 localizations. In five case, the operator was different from the operator for the initial duplex ultrasonography. Follow-up revealed: 1 new localization, 37 narrowings and 6 repermeabilizations.

DISCUSSION

The coherence of the duplex ultrasonographic follow-up and the presence of images compatible with partial thrombus on the revised phlebograms which had been initially interpreted as wash out flow constitute a group of arguments suggesting that the discrepancies observed should be considered as phlebography false-negatives. This defect in the sensitivity of phlebography has been reported by others in the literature both for distal and proximal localizations.

The in vivo metabolic pattern of low-grade brain gliomas: a positron emission tomographic study using 18F-fluorodeoxyglucose and 11C-L-methylmethionine

OBJECTIVE

The object of the present study was to identify metabolic differences between low-grade astrocytomas and oligodendrogliomas and to improve their diagnosis and noninvasive assessment, because both types of tumors look very similar from the point of view of clinical and radiological data (as assessed by computed tomography and magnetic resonance imaging).

METHODS

Before any aggressive treatment, 22 patients with primary low-grade gliomas (astrocytomas in 12 patients and oligodendrogliomas in 10) were investigated with positron emission tomography for both glucose metabolism (18F-fluorodeoxyglucose) and amino acid uptake (11C-L-methylmethionine). An original software that allows a full metabolic analysis of the tumor region of interest (defined from the T1-weighted magnetic resonance image) and compares tumor tissue uptake tracer concentrations with average healthy tissue values has been implemented for data processing. Heterogeneity of each individual tumor has been taken into account and was expressed in histograms, which provided data about the mean and also extreme and intermediate values of tracer concentrations and the way these values are distributed among the full tumor mass.

RESULTS

It has been shown that both tumor types exhibit a glucose hypometabolism (slightly more pronounced with astrocytomas), whereas they strongly differ in methionine uptake, which is high in all oligodendrogliomas and either decreased, normal, or moderately increased in astrocytomas. This latter metabolic difference between both tumor populations may be partially explained by their different cell densities.

CONCLUSION

This study suggests that despite similar radiological and clinical presentations, these two kinds of low-grade gliomas are metabolically different and could therefore have specific responses to different therapies. Moreover, their in vivo metabolic follow-up with positron emission tomography should rely on different parameters, depending on their histological type; methionine uptake may be more relevant than glucose metabolism in the follow-up of oligodendrogliomas.