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O Louis

Publications and source records attributed to O Louis.

10 recordsLinked to original sources
PubMed1992

[Bacillary angiomatosis: apropos of a case].

We report a case of bacillary angiomatosis (BA), a recently described opportunistic infection, in a 30-year-old patient with Aids who was referred for a purplish vascular nodule on the forehead, of one-month duration, surrounded by similar smaller papules. For the previous 4 months he had suffered from progressive cachexia with fever, chills, night sweats, arthralgias and bone pain for which no infectious or malignant cause had been discovered after an extensive medical work-up. Histological examination of the skin lesions using Warthin-Starry staining revealed lobular vascular proliferation and protuberant endothelial cells with clumps of small bacilli. These findings were confirmed by electron microscopy. We believe that this is the first case of BA diagnosed in Switzerland and discuss the skin lesions, systemic symptoms and evolution under antibiotic treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Dual-energy X-ray absorptiometry of lumbar vertebrae: relative contribution of body and posterior elements and accuracy in relation with neutron activation analysis.

The bone mineral content of 34 lumbar vertebrae obtained from ten cadavers (three men, seven women; age 61-88 years) was measured using a pulsed source dual-energy X-ray absorptiometry (DEXA) apparatus. Scanning was performed in the frontal projection and was repeated on the vertebral bodies obtained after removal of the posterior elements of the vertebrae. Subsequently a nondestructive neutron activation analysis (NAA) was performed. The mineral content of the vertebral bodies was found to represent (mean, SEM) 53.0% (1.9%) of the content of the whole vertebrae. The mineral content of the vertebral bodies assessed with NAA (BMC NAA) and with DEXA (BMC DEXA) showed a high correlation: BMC NAAA = (1.016 x BMC DEXA) + 0.990 r = 0.949 (p less than 0.001). We conclude that the mineral content of lumbar vertebral bodies can be accurately measured in vitro in a water environment by DEXA, and that the mean contribution of the posterior elements of the vertebra to the calcium hydroxyapatite content of whole vertebrae measured in the frontal projection is as high as 47.0%.

Absorptiometry, Photon↗
PubMed1991

Low vertebral bone density values in young non-elite female runners.

Thirty-five female runners (26.6 +/- 0.9 years, range 17-35) were scheduled for bone mineral density evaluation, using quantitative computed tomography of the lumbar spine. In 17 women with oligo-amenorrhea, vertebral bone mineral density was under the normal range (defined from a control group of 46 sedentary healthy females in the same age range), while it was within the normal range in all runners with regular menses (n = 18). When age classes were considered, all runners aged 17-21 (11/11) were found to have oligo-amenorrhea and low bone mineral density values, the difference in mineral density with the controls of the same age quartile being highly significant (p less than 0.001). Runners from the two youngest age classes (17-21 and 22-26) had started training early after menarche (0.9 +/- 0.6 and 2.5 +/- 1.6 years, respectively). These results show that very young female runners with oligo-amenorrhea may have impressively low bone mineral density values. The possibility that early onset of training, close to menarcheal age, might be a risk factor for low mineral density, deserves further investigation.

Adolescent↗
PubMed1989

Bone loss in young hypoestrogenic women due to primary ovarian failure: spinal quantitative computed tomography.

Vertebral bone mineral density was investigated in 22 young (29.3 +/- 1 years) women with primary ovarian failure, attending for infertility. The lumbar spine was studied, using a preprocessing dual-energy quantitative computed tomography technique and assessing vertebral bone mineral density from the reconstructed 125-kV image. Previously untreated women had significantly (P less than 0.001) lower values than a group of age-matched healthy controls, while the difference between those women having received estrogen therapy and the same controls was not significant. Sixteen patients were restudied after 6 to 21 months of estrogen therapy, part of a regimen intended to prepare the endometrium for oocyte donation, and vertebral bone mineral density increased in 12 of them. The authors conclude that primary ovarian failure is a cause for bone loss in these young women and that estrogen therapy is effective.

Adult↗
PubMed1989

Reference values for trabecular and cortical vertebral bone density in single and dual-energy quantitative computed tomography.

The validity of reference values for vertebral bone mineral density (BMD) reported in the literature has frequently been questioned. The introduction of dual-energy methods, new calibration systems, and automated image evaluation algorithms, has also made it necessary for us to re-evaluate BMD values in a normal population. We present patient selection criteria, CT measurement and evaluation protocols and results of single energy (SEQCT) and dual energy quantitative CT (DEQCT) for trabecular (tBMD) and cortical (cBMD) bone density in 135 males and 139 females. For SEQCT, tBMD loss rates of 1.7 and 1.8 mg/ml per year for males and females, respectively, were determined by linear regression. The respective DEQCT data show smaller decrements with age. Different statistical models for tBMD in females were tested; models based on a multiphase variation of tBMD yielded an improvement of the fit. For cBMD the percent rate of loss with age is much smaller than for tBMD; females showed a significantly higher loss rate than males, however. A comparison of our results with published data is included.

Absorptiometry, Photon↗
PubMed1988

Reproducibility of CT bone densitometry: operator versus automated ROI definition.

Intrasubject reproducibility with repeated determination of vertebral mineral density from a given set of CT images was investigated. The region of interest (ROI) in 10 patient scans was selected by four independent operators either manually or with an automated procedure separating cortical and spongeous bone, the operators being requested to interact in ROI selection. The mean intrasubject variation was found to be much lower with the automated process (0.3 to 0.6%) than with the conventional method (2.5 to 5.2%). In a second study, 10 patients were examined twice to determine the reproducibility of CT slice selection by the operator. The errors were of the same order of magnitude as in ROI selection.

Algorithms↗
PubMed1985

Diabetes insipidus from metastatic oat cell carcinoma: recovery after brain irradiation.

A hypothalamic metastasis was demonstrated by computed tomography in a 71-year-old patient, with previously unknown small cell lung cancer, who presented with diabetes insipidus and biological signs of hypothyroidism and hypogonadism. Brain irradiation resulted in resolution of polyuria, elevation of thyroid hormones, improvement of pituitary responsiveness to hypothalamic releasing hormones, and complete disappearance of contrast-enhanced suprasellar metastasis.

Aged↗