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Biomedical subjects

M Laroche

Publications and source records attributed to M Laroche.

At least 19 recordsLinked to original sources
PubMed2001

Phosphate, the renal tubule, and the musculoskeletal system.

A component of ATP, phosphate is at the hub of the energy-related mechanisms operative in muscle cells. Together with calcium, phosphate is involved in bone tissue mineralization: thus, a chronic alteration in the metabolism of phosphate can induce bone and joint disorders. Diagnosis of chronic hypophosphatemia. Serum phosphate, calcium, and creatinine should be assayed simultaneously. Serum calcium is increased in hypophosphatemia caused by hyperparathyroidism and decreased in osteomalacia. Urinary phosphate excretion should be measured in patients with a normal serum calcium level and a serum phosphate level lower than 0.80 mmol/L. A decrease in urinary phosphate excretion to less than 10 mmol/24 h strongly suggests a gastrointestinal disorder, such as malabsorption, antacid use, or chronic alcohol abuse. In patients with a urinary phosphate excretion greater than 20 mmol/24 h, the maximal rate of tubular reabsorption of phosphate (TmPO4) and the ratio of TmPO4 over glomerular filtration rate (GFR) should be determined to look for phosphate diabetes. Manifestations and causes of phosphate diabetes in adults. Moderately severe phosphate diabetes in adults manifests as chronic fatigue, depression, spinal pain, and polyarthralgia, with osteoporosis ascribable to increased bone resorption. Although many cases are idiopathic, investigations should be done to look for X-linked vitamin D-resistant rickets missed during childhood, a mesenchymatous tumor, or Fanconi's syndrome with renal wasting of phosphate, glucose, and amino acids. Management of phosphate diabetes. Phosphate supplementation and, in patients with normal urinary calcium excretion, calcitriol produce some improvement in the symptoms and increase the bone mineral density. Whether dipyramidole is clinically effective remains unclear.

Humans↗
PubMed2001

Increased vascularization in myeloma.

Several studies have shown that the number of intratumoral vessels can predict the aggressiveness of a solid cancer, development of metastases and patient survival. Does angiogenesis play an important role in myeloma? The aim of our study was to quantify bone marrow vascularity in various stages of proliferative plasma cell disorders (monoclonal gammopathies of undetermined significance (MGUS), stage I multiple myeloma (MM), stage III MM and Waldenström's macroglobulinemia (WM)) and to compare it with that of patients with osteoporosis. The study included 15 MGUS patients, 15 patients with stage I MM, 15 patients with symptomatic stage III MM, 7 patients with WM, 10 patients with osteoporosis, and 10 patients with reactive bone marrow (RBM), matched for sex and age. After iliac crest biopsy, the various vessels (arterioles, capillaries and sinusoids) were labeled with monoclonal antibodies CD34 and counted, and a histomorphometric study was done. The number of arterioles and arterial capillaries was significantly increased in MGUS and myeloma compared with osteoporosis. The number of arterioles and arterial capillaries increased moderately according to the stage of gravity of myeloma. The number of arterioles is negatively correlated with the trabecular bone volume and positively correlated with the eroded surfaces.

Adult↗
PubMed2001

Whole body and regional bone mineral density in ankylosing spondylitis.

OBJECTIVE: To study the regional distribution of bone mass and look for factors leading to bone loss in ankylosing spondylitis (AS). METHODS: Thirty-nine patients, all men, aged 20 to 55 years and presenting with AS were studied. Four hundred sixteen gendarmes, all men aged 20 to 55 years, formed an age matched control population used to define standard values for bone mineral density (BMD) in men. The patients with AS and the controls underwent measurement of whole body BMD and regional BMD by dual-energy x-ray absorptiometry. RESULTS: AS was associated with spinal bone loss, with lumbar spine BMD (LSBMD) 1.085 +/- 0.178 g/cm2 in the AS group compared with 1.232 +/- 0.136 g/cm2 in the control group (p < 0.01). Whole body BMD and regional BMD of head, whole spine, pelvis, and legs were reduced, although this was not statistically significant. Using standard values for LSBMD from the controls, we found that 46% (18/39) of patients with AS had Z score < -1.5 SD. Biological markers of disease activity were higher in the subgroup of patients with low LSBMD than in the subgroup with normal LSBMD, with an erythrocyte sedimentation rate of 29.4 +/- 23.4 mm/h versus 12.1 +/- 10.8 mm/h (p < 0.05) and C-reactive protein at 24.8 +/- 18 mg/l versus 12.7 +/- 14.2 mg/l (p < 0.05). CONCLUSION: AS is associated with bone loss, mainly concerning the lumbar spine, in patients whose disease is biologically most active.

Adult↗
PubMed2000

Acquired lumbar kyphosis caused in adults by primary paraspinal myopathy. Epidemiology, computed tomography findings, and outcomes in a cohort of 23 patients.

UNLABELLED: Acquired lumbar kyphosis in adults, also called bent spine syndrome (BSS), is probably due to primary tardive myopathy affecting the paraspinal muscles. OBJECTIVES: To define family history and other factors associated with BSS, to score functional disability and pain in BSS using visual analog scales (VASs), to determine the pace of disease progression during follow-up, and to define computed tomography (CT) findings comparatively with age- and sex-matched controls. PATIENTS AND METHODS: Twenty-three patients (20 women and three men; mean age, 72.8 years) with a mean disease duration of 8.1 years at presentation and a mean follow-up of 3.5 years underwent a medical interview, a physical examination, and yearly CT scans with muscle density measurement at several vertebral levels (T4, T10, L1, L3, and L5). RESULTS: Mean age at BSS onset was 64.6 years (range, 56-72). In 12 of the 23 cases, a family history of BSS was highly likely. Thirteen patients had performed heavy manual labor at some time during their lives. At completion of follow-up, the mean functional VAS score was 74.5 mm, the mean Eifel score was 16/24, and the mean pain VAS score was 72.4 mm. Mean muscle density obtained by pooling measurements at all vertebral levels was -12.6 +/- 31 Hounsfield units (HU) in the patients and +36.9 +/- 21 HU in the controls. During the 3.5-year follow-up, the mean loss in muscle density was 6.9 +/- 16 HU in the patients; in contrast, no muscle density difference was found between two groups of low back pain patients without BSS aged 65 years and 72 years, respectively (36.2 +/- 15 HU vs 38.6 +/- 26 HU). CONCLUSION: BSS causes major functional disability and pain, which worsen over time. The decrease in paraspinal muscle density extends along the entire spine and becomes increasingly marked over time.

Aged↗
PubMed1999

Interleukin-1beta, interleukin-1 receptor antagonist, interleukin-4, and interleukin-10 gene polymorphisms: relationship to occurrence and severity of rheumatoid arthritis.

OBJECTIVE: To test if interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL-1Ra), IL-4, or IL-10 gene polymorphisms could be used as markers of susceptibility or severity in rheumatoid arthritis (RA). METHODS: The study included 108 patients with early RA followed up for 2 years and 128 healthy controls. From genomic DNA, 6 polymorphisms in genes for IL-1beta, IL-1Ra, IL-10, and IL-4 were typed. Allelic frequencies and carriage rates were compared between RA patients and controls, between patients with erosive and nonerosive RA, and between patients with or without sustained remission. RESULTS: The RP1 allele of the IL-4 gene was found with a significantly higher frequency in RA patients compared with controls. The combination of an RA-related HLA-DR allele expressing shared epitope and the presence of allele E2 in IL-1beta exon 5 was found to expose patients to an increased risk of erosive disease, with an odds ratio of 8.20 (95% confidence interval 2.59-25.84, P < 0.0001). No significant association was observed between polymorphisms and the occurrence of sustained remission. CONCLUSION: This report, for the first time, indicates an association between RA and a polymorphic IL-4 gene sequence located in 5q31-33. In addition, the results show the prognostic value of a polymorphism in IL-1beta exon 5, which allowed prediction of erosive disease with a specificity of 91.8% in 42.1% of patients. Although these observations are very interesting, they have to be considered preliminary and will need to be confirmed.

Arthritis, Rheumatoid↗
PubMed1999

Measurement of bone mineral density by dual X-ray absorptiometry in Paget's disease before and after pamidronate treatment.

Third-generation bisphosphonates are now currently used in the treatment of Paget's disease of bone. Dual X-ray absorptiometry may make it possible to quantify the action of these bisphosphonates on bone mineral density (BMD) in pagetic and nonpagetic bone. We used Lunar DPX, a total-body software program (automatic analysis and/or manual windows according to the site and bilateral or unilateral pagetic involvement) to study BMD in 28 patients (18 men, 10 women, mean age 69.8 years) with Paget's disease before and 6 months after infusions of 60 mg (alkaline phosphatase <350 IU) or 120 mg (ALP >350 IU) of pamidronate. Before treatment, in the 28 patients, the BMD of trabecular pagetic bone was 25% higher than that of nonpagetic bone; in cortical pagetic bone the BMD was 35% higher. After treatment, the BMD of trabecular pagetic bone increased by only 1.17%. the BMD of cortical pagetic bone increased by 1.37% whereas nonpagetic cortical bone lost 0.84%, independently of the levels of parathyroid hormone or the administration of calcium and vitamin D.

Absorptiometry, Photon↗
PubMed1999

Rheumatoid factor and antikeratin antibody are independent from presence of DR4 or DR1 in rheumatoid arthritis.

BACKGROUND: Presence of HLA-DR4, rheumatoid factor, and antikeratin antibody may predict severe rheumatoid arthritis. OBJECTIVE: To investigate potential associations between HLA DR4, rheumatoid factor and antikeratin antibody in rheumatoid arthritis patients. PATIENTS AND METHODS: Retrospective review of 169 patients followed at the Rangueil Teaching Hospital rheumatology department for rheumatoid arthritis. RESULTS: No differences in prevalences of DR4 and DR1 were found between patients with and without rheumatoid factor or between patients with and without antikeratin antibody, suggesting that the production of rheumatoid factor and/or antikeratin antibody is not dependent on genetic factors. Substantial overlap was seen between rheumatoid factor and antikeratin antibody. All three parameters can be identified at first evaluation of a patient with joint disease. CONCLUSION: It would be of interest to evaluate the cumulative predictive value of DR4 or DR1, rheumatoid factor and antikeratin antibody at disease onset.

Arthritis, Rheumatoid↗
PubMed1999

[Steinert disease associated with Klinefelter's syndrome].

Hypogonadism is common in Steinert disease but may also suggest other diagnoses. We report the case of a patient with Steinert's disease who also had Klinefelter syndrome disclosed at 62 years of age by an osteoporotic fracture. Both clinical diagnoses were confirmed by karyotype and genetic analysis. The hypogonadism assigned to the Klinefelter syndrome for this patient may have influenced the clinical expression of the muscular pathology.

Chromosome Aberrations↗
PubMed1998

[Gammopathies of indeterminant significance and osteoporosis: association or coincidence?].

OBJECTIVES: Osteoporosis is common in subjects over 70 years of age. Likewise, the incidence of monogammapathies of undetermined signification (MGUS) increases with age. We conducted this study to determine whether the biological and histomorphometric characteristics of osteoporosis in patients with MGUS are different from those in primary osteoporosis and to ascertain whether any cause and effect relationships could exist between MGUS and osteoporosis, excluding signs of active myeloma. PATIENTS AND METHODS: Serum and urinary phosphorus and calcium, histomorphometric measurements, hormone levels and serum cytokines (IL1, IL6 and TNF alpha) were determined in 7 patients (mean age 71.8 years, 2 men and 5 women) with MGUS associated with osteoporosis with vertebral fractures (OP) and compared with those in 7 osteoporosis patients without MGUS matched for age, sex, and osteoporosis severity and 7 other age and sex matched patients with MGUS without OS. The MGUS + PS patients were followed for 9 years (4.5 to 20) so slowly progressive myeloma could be excluded. RESULTS: Cytokine levels were the same in the three groups of patients but MGUS + OP patients had higher urinary calcium levels (ca/cr = 0.21 +/- 0.08 vs 0.12 +/- 0.1 (OP) and 0.13 (MGUS); p = 0.04), decreased osteocalcin levels (7 +/- 4.6 ng/ml vs. 12 +/- 4 (OP) and 11.5 +/- 5 (MGUS); p = 0.01) and increased surface resorption (8 +/- 1.4 vs. 3.6 +/- 1.2 (OP) and 5.5 +/- 1.7 (MGUS); p = 0.05). DISCUSSION: It has been demonstrated that MGUS in patients with increased resorption and lower osteocalcin levels frequently progresses to active myeloma. The question is raised as to whether, in certain cases of MGUS, in situ stimulation of bone cells by monoclonal plasma cells could exist without ongoing transformation to active myeloma.

Aged↗