The role of cumulative physical work load in lumbar spine disease: risk factors for lumbar osteochondrosis and spondylosis associated with chronic complaints.

OBJECTIVES: To investigate the relation with a case-control study between symptomatic osteochondrosis or spondylosis of the lumbar spine and cumulative occupational exposure to lifting or carrying and to working postures with extreme forward bending. METHODS: From two practices and four clinics were recruited 229 male patients with radiographically confirmed osteochondrosis or spondylosis of the lumbar spine associated with chronic complaints. Of these 135 had additionally had acute lumbar disc herniation. A total of 197 control subjects was recruited: 107 subjects with anamnestic exclusion of lumbar spine disease were drawn as a random population control group and 90 patients admitted to hospital for urolithiasis who had no osteochondrosis or spondylosis of the lumbar spine radiographically were recruited as a hospital based control group. Data were gathered in a structured personal interview and analysed using logistic regression to control for age, region, nationality, and other diseases affecting the lumbar spine. To calculate cumulative forces to the lumbar spine over the entire working life, the Mainz-Dortmund dose model (MDD), which is based on an overproportional weighting of the lumbar disc compression force relative to the respective duration of the lifting process was applied with modifications: any objects weighing >or=5 kg were included in the calculation and no minimum daily exposure limits were established. Calculation of forces to the lumbar spine was based on self reported estimates of occupational lifting, trunk flexion, and duration. RESULTS: For a lumbar spine dose >9 x 10(6) Nh (Newton x hours), the risk of having radiographically confirmed osteochondrosis or spondylosis of the lumbar spine as measured by the odds ratio (OR) was 8.5 (95% confidence interval (95% CI) 4.1 to 17.5) compared with subjects with a load of 0 Nh. To avoid differential bias, forces to the lumbar spine were also calculated on the basis of an internal job exposure matrix based on the control subjects' exposure assessments for their respective job groups. Although ORs were lower with this approach, they remained significant. CONCLUSIONS: The calculation of the sum of forces to the lumbar spine is a useful tool for risk assessment for symptomatic osteochondrosis or spondylosis of the lumbar spine. The results suggest that cumulative occupational exposure to lifting or carrying and extreme forward bending increases the risk for developing symptomatic osteochondrosis or spondylosis of the lumbar spine.

[The role of electron beam CT in the diagnosis of acute pulmonary embolism--presenting a new examination protocol]. / Wertigkeit der EB-CT in der Diagnostik der akuten Lungenembolie--Vorstellung eines neuen Untersuchungsprotokolls.

PURPOSE: To evaluate electron beam tomography in the detection of acute pulmonary embolism using a new acquisition protocol. MATERIALS AND METHODS: 65 patients underwent electron beam tomography (EBT) and v./p. scintigraphy. According to the inclusion criteria 46 patients participated in the study. Contrast enhancement and detectability of pulmonary arteries were scored on a 4 step scale for image quality. The results of prospective detection of pulmonary embolism were compared for both modalities (blinded reading). "Embolism", "questionable embolism" and "no embolism" were used as categories. RESULTS: 22/46 patients (48%) showed acute pulmonary embolism. EBT and scintigraphy were discordant in 24% of patients. In EBT 1 false positive and 1 false negative case occurred, scintigraphy demonstrated 2 false negative and 3 false positive cases. 6/9 patients with questionable findings in scintigraphy were correctly classified by EBT to a category "embolism" or "no embolism" as "suspected embolism", EBT displayed a sensitivity of 96.3% and a specificity of 94.7%. Scintigraphy evidenced a sensitivity of 93.7% and a specificity of 84.4%. CONCLUSIONS: EBT shows better results than scintigraphy for the detection of acute pulmonary emboli. The evaluated new acquisition protocol for EBT seems to be well suited. High vessel contrast and thin slices allow a reliable detection of segmental and subsegmental pulmonary arteries.

Ovarian growth and folliculogenesis in breeding and nonbreeding females of a social rodent, the Zambian common mole-rat, Cryptomys sp.

Zambian common mole-rats are subterranean rodents that live in families with only one female breeding. Her offspring remain in the parental nest and do not reproduce. Behavioral experiments (Burda, '95) demonstrated that their apparent "sterility" is based on incest avoidance and individual recognition of family members. To elucidate whether some kind of morphologically apparent ovarian suppression still takes place in daughters, ovaries of females of known age, weight, and reproductive histories were examined histologically and morphometrically. The body mass of old females (more than 3 years of age) begins to decrease, and the ovaries seem to begin to atrophy at the age of about 3-6 years. Ovaries in neonates exhibited primordial and primary follicles, sometimes clustered in nests. Ovaries of adult nonbreeding females expressed all stages of the follicular development up to tertiary follicles. Many unruptured luteinized follicles were present, but true corpora lutea as a morphological sign of ovulation were missing. Unruptured luteinized follicles also could be found (additionally to true corpora lutea) in ovaries of breeding females. The number of primordial follicles dropped rapidly during the first 2 years of age; the number of primary, secondary, and tertiary follicles was subject to individual variation; and there was no clear correlation with age or reproductive status. While a tendency to form accessory unruptured luteinized follicles may just reflect taxonomic affinities of bathyergids to hystricomorphs, the otherwise complete folliculogenesis in "sterile" daughters and the presence of unruptured luteinized follicles even in breeding females are further evidence that there is no hormonal suppression of the ovarial cycle. We suggest that ovulation in nonbreeding females is not actively suppressed by the breeding female, but instead that it is not released because the triggering mechanisms, most probably repeated copulation, are missing.