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Biomedical subjects

S Rozenberg

Publications and source records attributed to S Rozenberg.

At least 19 recordsLinked to original sources
PubMed1995

[Osteo-articular complications of heart transplantation].

Heart transplantation is an effective means of treating irreversible heart failure in selected patients. Preventing organ rejection requires immunosuppressor treatment with corticosteroids, azathioprine and/or cyclosporine. Bone and joint complications are frequent and increase overall morbidity directly related to anti-rejection therapy. Corticosteroids favour osteopenia which can be detected by measurement of bone density. The risks include spontaneous wedge fractures of the spine and aseptic necrosis. The frequency of complications has been reduced with the use of cyclosporine allowing a reduction in corticosteroids. Raised serum urate levels and increased risk of gout can be induced by cyclosporine. The gout in these patients has a particular course since it appears rapidly after only a few months of hyperuricaemia. Several joints may be involved with production of tophi. Treatment is particularly difficult. Its frequency increases after heart transplantation compared with other organs which can be explained by the more prevalent prescription of diuretics which further aggravate urate secretion. These complications cause further discomfort in transplant recipients.

Bone Diseases↗
PubMed1995

Precision and accuracy of in vivo bone mineral measurement in rats using dual-energy X-ray absorptiometry.

The aim of this study was to evaluate the precision and accuracy of dual-energy X-ray absorptiometry (DXA) for measuring bone mineral content at different sites of the skeleton in rats. In vitro the reproducibility error was very small (< 1%), but in vivo the intra-observer variability ranged from 0.9% to 6.0%. Several factors have been shown to affect in vivo reproducibility: the reproducibility was better when the results were expressed as bone mineral density (BMD) rather than bone mineral content (BMC), intra-observer variability was better than the inter-observer variability, and a higher error was observed for the tibia compared with that for vertebrae and femur. The accuracy of measurement at the femur and tibia was assessed by comparing the values with ash weight and with biochemically determined calcium content. The correlation coefficients (R) between the in vitro BMC and the dry weight or the calcium content were higher than 0.99 for both the femur and the tibia. SEE ranged between 0.0 g (ash weight) and 2.0 mg (Ca content). Using in vitro BMC, ash weight could be estimated with an accuracy error close to 0 and calcium content with an error ranging between 0.82% and 6.80%. The R values obtained between the in vivo and in vitro BMC were 0.98 and 0.97 respectively for femur and tibia, with SEE of 0.04 and 0.02 g respectively. In conclusion, the in vivo precision of the technique was found to be too low. To be of practical use it is important in the design of experimentation to try to reduce the measurement error.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

Clinical significance of heterogeneity of vertebral mineral density.

Important variations in Z-score per vertebra, which is a common expression of bone mineral density (BMD), are sometimes observed. The present study evaluates the clinical significance of this heterogeneity. Normal and osteoporotic subjects were defined by using strict criteria. For every scan, the minimal Z-score (the vertebra with the lowest Z-score) and the delta Z (highest Z-score--lowest Z-score) was calculated. Of the investigated subjects, 30% presented a delta Z > or = 1. No significant correlation could be found between delta Z and age, BMD, height and weight. There was no difference in delta Z between scans of good, average or poor quality. Osteoporotic subjects had significantly lowered BMD values, whether evaluated through Z-scores for the L2-L4 site (P < 0.001; t = 3.71) or by minimal Z-score (P < 0.001; t = 3.97). Reproducibility calculated for the L2-L4 site on phantoms as well as on patients was excellent (C.V. < 1%). When reproducibility was calculated on each vertebra in vitro or in vivo, an increase in variability was observed. These data show that marked heterogeneity in BMD per vertebra is not infrequent. In some subjects low BMD may be measured at certain vertebrae but not at the total site. Our data suggest that in those cases the lowest BMD should be considered. In follow-up studies however, the BMD should be calculated on the L2-L4 segment, since a loss of precision is observed when only one vertebra is measured.

Absorptiometry, Photon↗
PubMed1995

Silica-associated connective tissue disease. A study of 24 cases.

We prospectively studied all patients hospitalized for connective tissue disease (CTD) in our French rheumatology clinic from January 1979 to December 1989. Our aims were 1) to determine if CTDs associated with occupational exposure to silica (Si) are currently observed in a rheumatology clinic, and, if so, 2) to describe the major features of Si-associated CTD, and 3) to specify which individuals are affected by Si-associated CTD. Patients were divided into 2 groups based on their responses to a questionnaire: those who had been exposed to Si, and those who had no occupational exposure to Si. Among the 764 patients with CTD studied, 24 (3%) were patients with Si-associated CTD and 740 (97%) were patients with non-Si-associated CTD. The sex ratio between the 2 groups was significantly different with a high frequency of men and of immigrants in the Si-associated CTD group. Two thirds of the patients exposed to Si were male miners or sandblasters, but the other third had more unusual exposures to Si, which may involve members of all socio-economics sectors and both sexes, such as sculpture or exposure to abrasive powders. Progressive systemic sclerosis (PSS) was significantly more prevalent in the Si-associated CTD group. This group also consisted of patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), dermatomyositis (DM), and other autoimmune diseases. Si-associated CTD was characterized by the frequency of radiologic lung fibrosis, impaired pulmonary function tests, secondary Sjögren syndrome, and antinuclear antibodies. The number of mineral particles and crystalline Si content were raised in all the bronchoalveolar lavage specimens of Si-exposed patients but in none of those of nonexposed patients. In some cases of Si-associated CTD, the disease was reversible after early cessation of Si exposure. Epidemiologic studies are required to confirm our hypothesis that not only PSS and RA but also SLE and DM are associated with occupational exposure to Si. Pending such results, exposure to Si should be sought in the history of any patient with CTD, especially in a male patient with pulmonary signs, and if present, exposure should be stopped. In the meantime, steps should be taken to ensure that workers exposed to Si in all environments have adequate protection.

Adult↗
PubMed1995

Compliance to hormone replacement therapy.

Hormone replacement therapy (HRT) after menopause can effectively reduce climacteric-related symptoms and therefore increase quality of life. A large number of studies have also demonstrated that with a sufficient dosage bone loss can be prevented and fracture frequency reduced. Epidemiological and experimental studies also suggest a decrease in cardiovascular mortality and morbidity among HRT users compared to nonusers. From an epidemiological perspective, in order to obtain optimal prevention of osteoporosis and of cardiovascular diseases, a high proportion of postmenopausal women should be treated using long-term therapy. Surveys generally show that only a small proportion of postmenopausal women use hormone replacement therapy (in Belgium, around 14%) and that the long-term compliance to treatment, which is mandatory in the prevention due to low compliance remains unknown. The reasons why patients patients do not pursue their treatment in the long run remain unclear. Fear of cancer and drug-related side effects, such as unacceptable bleeding, have been among the most frequently mentioned causes. Thus, individual information on patients regarding HRT seems to be crucial issue. A few recent studies have suggested a favorable role of osteoporosis prevention and bone mass measurements to increase compliance, but this is not well established and will depend on the physician's attitude toward HTR and osteoporosis prevention. At present, very little is known about the physician's decision to treat postmenopausal women with HRT. Sometimes, the physician's attitude has been reported was very negative toward HRT-apparently, many physicians think HRT increases cardiovascular risk, even though most data suggest a reduction of cardiovascular risk among HRT users. Very little research has actually been performed on how to improve compliance. Education and behavioral strategies may be of use. Improved communication between patients and physicians, establishing a confidential relationship with patients, and the involvement of nursing counseling are all strategies which may improve compliance. The use of easy-to-take medication that induces no bleeding, supported by calendar devices or reminders, may facilitate chronic use of medication. Future research needs to investigate the physician's and patient's decision-making processes and the reasons for those decisions.

Estrogen Replacement Therapy↗
PubMed1995

Urate-oxidase for the treatment of tophaceous gout in heart transplant recipients. A report of three cases.

Gout in heart transplant recipients is common and poses a significant therapeutic challenge. Concomitant administration of azathioprine and allopurinol therapy carries a high risk of leukopenia. Uricosuric agents can cause renal lithiasis and/or acute renal failure in patients with renal failure and/or high urinary levels of uric acid. We report our experience with urate-oxidase in three heart transplant recipients with severe polyarticular and tophaceous gout, a history of leukopenia under allopurinol and unresponsiveness or contraindications to uricosuric agents. Urate-oxidase was given parenterally in a dosage of 1000 units per day, seven days a month. The injections were done intramuscularly in one patient and intravenously in the other two, who were under anticoagulant therapy. Patients 1 and 2 received 12 and 6 courses, respectively. The third patient had had four courses and was still under treatment at the time of this writing. Shrinking of the tophi and improved mobility of the fingers were seen in all three patients after the second course. No adverse effects were recorded. Our experience suggests that urate-oxidase therapy may decrease the urate burden in patients with severe tophaceous gout. Urate-oxidase therapy should be viewed as a phase in the treatment of gout, which must be followed by administration of another agent.

Adult↗
PubMed1994

[What remains of gout in 1993?].

Gout is a disease caused by deposits of sodium urate crystals in tissues. This disease, already known of Hippocrates, is now due to new causes, notably iatrogenic, and has new clinical forms. The typical initial attack usually occurs in men in their fifties and affects the big toe; in the absence of treatment it evolves towards chronic tophaceous gout. When gout occurs in subjects younger than 30 years, these must be investigated for enzyme deficit which is usually partial. The incidence of gout in women is ever increasing, being encouraged by treatments with diuretic drugs. Gout is often atypical, affecting predominantly the hands and with rapid development of tophus. In transplanted patients other drugs, such as cyclosporin, may induce an early, polyarticular and tophaceous gout. Alcohol is a facilitating factor of hyperuricaemia. Disturbances of metabolism, such as hyperlipidaemia, obesity or arterial hypertension, are often associated with hyperuricaemia. With an early and well-conducted treatment the passage to chronicity and the occurrence of complications can be avoided.

Acute Disease↗
PubMed1994

Cardiovascular protection by estrogen: a hemodynamic mechanism?

Cardiovascular risk is higher in men than in women, and also more prevalent in postmenopausal than in premenopausal women, especially if not treated by estrogens. These differences may be due, in part, to a cardioprotective action of sex hormones, mainly estrogens. However, only a limited part of this protection may be attributed to metabolic modifications induced by replacement therapy with estrogen. Therefore, it remains to be determined which other cardioprotective mechanisms influenced by sex steroids might be involved. It has been demonstrated that the menopause is associated with an increase in uterine arterial pulsatility index, reflecting increased peripheral resistance, while the administration of estrogens has an opposite effect at this level. In Doppler studies, estrogen replacement therapy was also associated with an increase in stroke volume and flow acceleration in the aorta. This suggests a positive inotropic effect of estrogens. Using technetium scanning, it was found that women at an early phase of menopause have a stronger myocardial contractility than women of a similar age whose menopause is of longer duration. These effects of estrogens on hemodynamic characteristics might be controlled by vasoregulatory hormones such as endothelin(s) or endothelial-derived relaxing factor (EDRF), now identified as nitric oxide (NO). Indeed, sex-associated differences in endothelin have been observed. Such are some of the mechanisms by which estrogen administration might effect a cardiovascular protection. At the present time, however, conclusive data are not available.

Cardiovascular Diseases↗
PubMed1993

Decrease of bone mineral density during estrogen substitution therapy.

A decrease in bone mineral density (BMD) in patients treated with hormone replacement therapy (HRT) is sometimes observed in clinical practice. In order to assess the frequency and the characteristics of these cases, we reviewed the data of 102 women treated with HRT for more than 2 years, and who had undergone at least 3 lumbar BMD measurements during that period. For each patient, a linear function was fitted to the BMD data in relation to time. The slope was calculated. There was an overall gain in BMD during treatment, mean (+/- S.E.M.) values of slope 0.007 g/cm2/year (+/- 0.002). Fifty-three patients had a slope higher than 0.005, 28 a slope close to 0 (between 0.005 and -0.005) and 21 a slope lower than -0.005. By dividing the patients in tertiles of slopes (tertile I: slope < 0; tertile II: 0 < slope < 0.011; tertile III: slope > 0.011), significant differences were observed between the three groups of slope for the initial BMD (P < 0.001), hydroxyproline/creatinine ratio (P < 0.01), weight, DHEAS and alkaline phosphatase (P < 0.05). Only 1 of the 15 patients with a low bone mass (lower than mean +/- 1 S.D.) had a negative slope, while 9 of the 16 with a high-bone mass (higher than mean +/- 1 S.D.), had a negative slope. Under HRT, about 21% of postmenopausal women have a slight decrease in BMD as assessed by DPA. Because of the DPA coefficient of variation, however, the exact number of bone losers cannot be determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1993

Bone mineral density measured by dual photon and dual energy X-ray absorptiometry: a problem of accuracy.

Dual photon absorptiometers (DPA) are currently being replaced by dual energy X-ray absorptiometers (DXA) for measurements of bone mineral density (BMD). In order to evaluate how to use the previously obtained BMD results by DPA (BMDo) in the follow-up of patients, the following study was performed. Ninety-five women who had had BMDo during the last 12 months were selected. L2-L4 BMD was measured twice on the same day using both DPA (BMDp) and by DXA (BMDx). BMDp was highly correlated to BMDx (R = 0.95; P < 0.001) but a wide variation of the ratio BMDp:BMDx was observed which ranged between 0.65 and 1.09 (mean 0.90, S.D. 0.05). There was no significant relationship between the ratio BDMp:BMDx and age or height but there was a significant relationship between this ratio and the weight of the patient (R = 0.31; P < 0.001). The results also indicated that the correlation between DXA and DPA was lower than that observed between the two DPA measurements (R = 0.98; P < 0.001) which, moreover, were not performed on the same day. These observations contrast with the relatively high precision of both instruments and have to be attributed to relative inaccuracy of one or probably both techniques.

Absorptiometry, Photon↗
PubMed1993

[Neurologic complications of osteoporotic spinal collapses. Apropos of 8 cases].

The prevalence of neurological complications in patients with osteoporotic vertebral collapse and the risk factors for neurological compromise were studied retrospectively in 138 inpatients. Six per cent of patients had objective neurological loss. Patients with neurological loss were more likely to have changes suggestive of malignant disease on roentgenograms, computed tomography, and magnetic resonance imaging. Diagnosis was based on magnetic resonance imaging and examination of vertebral biopsy specimens. Comparison of patients with and without neurological loss suggested that an intravertebral vacuum phenomenon and/or a cortical osteoporosis may cause fracture of the posterior wall and therefore compression of neurological structures.

Aged↗
PubMed1993

[Rheumatologic manifestations in heart transplant recipients. A cross-sectional study of 365 patients].

Rheumatological complications are sometimes disabling in heart transplant recipients and may negate the good results obtained with transplantation. The objective of this study was to evaluate the incidence of these complications. 365 consecutive heart transplant recipients (292 males and 73 females) were systematically interviewed and examined according to a standardized protocol. The mean age of the patients was 45.9 +/- 12.0 years (range: 11-68). The mean duration from transplantation to time of the study was 35.8 +/- 25.6 months (range: 1-115). The rheumatological disorders most frequently encountered were: gout, osteoporosis, osteonecrosis and myalgias. Early-onset polyarticular gout was diagnosed in 63/365 patients (17.3%). This diagnosis was significantly associated with patient's age, time since transplant, male sex, serum uric acid, serum creatinine, diuretics intake and inversely associated with the serum cyclosporin levels. Hyperuricemia was observed in 75.9% of transplant recipients with a mean of 507.5 +/- 132.5 mumol/l (range: 97-965). An osteoporotic fracture was present in 18/365 patients (4.9%) and was significantly associated with the patient's age, but not with the dose of corticosteroids. Osteonecrosis was detected in 10/365 patients (2.7%), always affected the hip, and was significantly associated with the patient's age, but not with the high doses of steroids. Myalgias were reported by 14/365 patients (3.8%). Laboratory, electromyographic and histological analysis were negative. Rheumatological complications are frequent in heart transplant recipients and justify preventive and therapeutic management.

Adolescent↗
PubMed1992

Risk of osteoporosis in men with chronic bronchitis.

Theoretically, patients with chronic bronchitis are at risk for osteoporosis. Bone metabolism was assessed in 44 male chronic bronchitics treated with oral prednisolone (C+; n = 19) or with bronchodilatory drugs alone (C-; n = 25). In both groups, serum osteocalcin was lower (p less than 0.001) than in age- and sex-matched controls (mean (ng/ml) C+ 1.0, C- 1.9, controls 4.2), while testosterone was at the lower limit of the reference range. Low trabecular bone mineral density (BMD) was noted in the C- group (median Z score -1.0), but both cortical and trabecular BMD were depressed in the C+ group (-1.0 and -1.4, respectively). In conclusion, chronic bronchitics treated with corticosteroids, even at low doses, are at risk for osteoporosis. In both groups, additional factors such as hypogonadism might be responsible for low BMD and low osteocalcin levels. A decrease in bone formation is a possible mechanism of action.

Adrenal Cortex Hormones↗