Influence of body parameters on female peak bone mass and bone loss.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
C Trevisan
Publications and source records attributed to C Trevisan.
Evaluation of a model for prediction of lumbar bone mineral density.
Explore the source record for details and available documents.
Absorptiometry, Photon↗
Bone mass measurement by DXA: influence of analysis procedures and interunit variation.
Interunit variability among bone densitometers is due to different factors, including different calibration procedures and algorithms and variability in photon source energies and/or intensities. Other factors, such as the choice of scan parameters or the analysis procedures, can also introduce variability. The new generation of dual-energy x-ray absorptiometry (DXA) has partially improved this situation. The aim of this study was to investigate the operator-dependent analysis procedures that can affect scan results and to evaluate the phantom and in vivo interunit variation of some DXA instruments. Four DXA instruments (QDR 1000 and 1000/W, Hologic, Inc.) were used. Potential sources of variability in the analysis procedures of anteroposterior lumbar spine and hip scans were considered: in most cases these procedures significantly influenced scan results. On lumbar spine, an enlargement of the scan window of less than 3 cm was responsible for an average increase in bone mineral density (BMD) of about 3%. On the hip, lowering the scan window by about 1 cm accounted for an increase in the whole-segment BMD of about 4%. After standardization of analysis procedures, interunit and intraunit coefficients of variation and percentage differences among instruments were less than 1% for all the parameters considered (area and bone mineral content and density) with both an anatomic and a geometric phantom, and in nine subjects scanned by two different devices the percentage difference in BMD was greater than 2%. This study shows that present interunit variability allows comparisons among laboratories, but only if highly standardized analysis procedures are used.
Absorptiometry, Photon↗
Bone mass status in different degrees of chronic renal failure.
Bone mineral density (BMD) was evaluated in 69 patients with chronic renal failure (CRF) and in healthy controls matched for age, sex, and, for women, menopausal status. Both appendicular (predominantly cortical) and axial (predominantly trabecular) bone mass were measured. Appendicular BMD was measured by single photon absorptiometry on the distal forearm and axial BMD was measured by dual photon absorptiometry on the lumbar spine. Patients were divided into three groups on the basis of creatinine clearance: group 1, 58 to 36 ml/min; group 2, 30 to 18 ml/min; group 3, 15 to 9 ml/min. Both appendicular and axial BMD decreased with the worsening of renal failure. Parathyroid hormone levels were inversely correlated with the values of appendicular BMD. BMD values were significantly lower in postmenopausal than in premenopausal women. Months of menopause were inversely correlated with axial BMD values. Appendicular BMD was lower in CRF patients than in controls, and both appendicular and axial BMD were significantly lower in postmenopausal uremic women than in postmenopausal healthy women.
Absorptiometry, Photon↗
Epidemiology of spinal muscular atrophies in a sample of the Italian population.
In the course of an epidemiological survey in four provinces of Veneto (northeastern Italy) 67 spinal muscular atrophy (SMA) cases (types I, II and III) were recorded. The survey spanned the period 1960-1983 and involved 859,891 consecutive live-born infants in a population of 2,635,800 inhabitants. The overall prevalence at birth for SMA types I, II and III was 7.8/100,000 live births. Type I alone accounted for 4.1/100,000 live births. If the hypothesis that SMA types I, II and III are clinical manifestations of allelic mutations is assumed, the mutation rate would be about 70 x 10(-6) and the frequency of the heterozygotes 1 in 57.
Female↗
Age, time since menopause, and body parameters as determinants of female spinal bone mass: a mathematical model.
The study of mathematical models to describe bone mass behavior throughout life is a possibility for assessing the main factors of peak bone mass and bone loss. We developed a mathematical model to predict spinal bone mass behavior on a sample of 181 healthy Italian women whose lumbar bone mineral content was determined by Gd-153 dual photon absorptiometry. This model proved to be both efficient, showing the best fit (r = 0.7 on spinal bone mineral content) when compared to other previously suggested models, and also reliable as its fit remained the best when applied to a subsequent sample of 519 women whose lumbar spine was measured by dual X-ray photon absorptiometry. This model suggests that body height and body weight (but not age) are determinants of bone mass in premenopausal women. In postmenopausal women, an accelerated phase of bone loss starting at menopause is dependent on age and time since menopause, whereas body mass index acts as a protective factor. This model confirms the influence on spinal bone mass not only of age and time since menopause but also of body size parameters.
Absorptiometry, Photon↗
Spinal and forearm bone mass in relation to ageing and menopause in healthy Italian women.
Most studies concerning bone status have been performed in Nordic and Anglo-Saxon countries and few data are available on southern European populations. We performed a cross-sectional study on spine and forearm bone mass in 234 healthy Italian women and related the results to age and time since menopause. Forearm bone mass does not decline in premenopausal age, whereas, as far as the spine is concerned, a significant reduction appears 3 years before the mean age of menopause; in both cases, the occurrence of menopause accounted for an accelerated phase of bone loss. In postmenopausal women both spine and forearm bone mass show a stronger correlation with years since menopause than with age. According to a linear exponential model, the rate of spinal bone loss per year since menopause is around 4% in the first 3 years which slows down to around 2% in the 5th year; the corresponding rates of forearm bone loss are 2% and 1.3%, respectively.
Adult↗
Gonadotropin releasing hormone agonist therapy and its effect on bone mass.
The effects on bone mass of a 6 month therapeutic cycle with a gonadotropin releasing hormone agonist (GnRHa) were studied in 22 patients, ten affected by pelvic endometriosis and 12 by uterine fibroids. All patients were subjected to preliminary full examinations to confirm their diagnosis (laparoscopy for the endometriosis group and precise ultrasound volume measurements for uterine fibroids group). Before the beginning of treatment, bone mineral density (BMD) was measured in each patient both on the distal third of the forearm, with single-photon absorptiometry, and on the lumbar spine (L1-L4), with dual photon absorptiometry. The gonadotropin releasing hormone agonist used was buserelin. In the first week of therapy 0.5 mg of the drug was administered subcutaneously thrice daily. In the following 25 weeks the same drug was given intranasally, at a dosage of 300 micrograms again three times a day. Bone mass measurements, both at the peripheral and at the axial site, were repeated at the end of the 26-week therapeutic cycle and then again 6 months later. At the 26th week, a significant decrease of BMD was observed at both sites. The loss was 1.5% (p less than 0.05) on the lumbar spine, and 2.1% (p less than 0.05) on the radius. No bone mass restoration took place in the following 6 months. On the contrary, a less significant but discernible trend towards a further bone loss was apparent in the BMD values measured 6 months after the end of therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Louis-Bar syndrome: spontaneous and induced chromosomal aberrations in lymphocytes and micronuclei in lymphocytes, oral mucosa and hair root cells.
Louis-Bar (L-B) syndrome, also called ataxia-telangiectasia, is cytogenetically characterized by an increased frequency of spontaneous and induced chromosomal aberrations (CA) in cultured lymphocytes and skin fibroblasts. However, it is not yet clear whether the chromosomal instability is also present in uncultured cells. The spontaneous and bleomycin-induced CA in peripheral lymphocytes of 8 L-B patients were evaluated. The micronucleus test was also performed, for the first time in lymphocytes by the cytokinesis-block method, and in uncultured cells of the oral cavity and hair root. The spontaneous frequency of CA and micronuclei in lymphocytes was about 3 times higher in L-B patients than in controls, these two cytogenetic parameters being highly correlated. Moreover, the induction by bleomycin of CA was higher in patients than in controls. The micronuclei in buccal and hair root cells of patients were normal. It remains to be determined whether the different responses obtained with cultured and uncultured cells are the result of the different L-B gene expression of chromosomal instability or whether they arise because of a particular cell sensitivity to culture conditions. The spontaneous and induced CA in lymphocytes of heterozygotes cultured in the presence of L-B serum were studied to evaluate a possible increased sensitivity of heterozygotes to a possible diffusible clastogenic factor present in the plasma of L-B patients. We could not demonstrate the presence of any factor that enhances CA in normal subjects or in heterozygote carriers.
Adolescent↗
Endocrine function and morphological findings in patients with disorders of the hypothalamo-pituitary area: a study with magnetic resonance.
Evaluation of the sellar area was performed with magnetic resonance imaging in 101 patients (age range 0.8-27 years) with hypopituitarism, isolated diabetes insipidus, hypogonadotrophic hypogonadism, and central precocious puberty. The hypopituitary patients (n = 70) included multiple pituitary deficiency (n = 23), pituitary deficiency with diabetes insipidus (n = 5), and isolated growth hormone deficiency (n = 42). The patients with multiple pituitary deficiency showed pathological morphological findings in all cases, with stalk and posterior lobe always involved. The group with associated diabetes insipidus had abnormal stalk in four of five cases and posterior lobe not visible in all cases. Only five of 42 (12%) patients with isolated growth hormone deficiency had abnormalities of the sellar area. In two out of four patients with isolated diabetes insipidus posterior lobe was not seen. All patients with hypogonadotrophic hypogonadism (three with Kallmann's syndrome, one Prader-Willi syndrome, and two idiopathic hypogonadism) appeared normal. In precocious puberty (n = 21) the three patients with onset of symptoms before age 2 years exhibited a hypothalamic hamartoma, whereas in the others with onset of puberty between age 2 and 7 the magnetic resonance image was normal in 17 of 18 patients. The probability of finding a pathological magnetic resonance image was considerably high in our patients with multiple pituitary deficiency, isolated diabetes insipidus, and precocious puberty with very early onset of symptoms. On the contrary, purely functional abnormality is suggested in most patients with isolated growth hormone deficiency, hypogonadotrophic hypogonadism, and precocious puberty with later onset of symptoms.
Adolescent↗
Acute Fisher's syndrome during the course of chronic uremia: is the hemodialysis implicated in onset and relapses?
An uremic patient, in chronic dialytic treatment, developed a Miller-Fisher's syndrome acutely after a dialysis. Clinical diagnosis was supported by findings of persistent conduction block in upper and lower extremities and by raised proteins in CSF. Contrast-enhanced CT and MRI scans excluded lesions in the brain stem. The course of this illness was characterized by waxing and waning in cranial nerve deficits, in relation with the hemodialytic treatments. We suggest that, when the patient recovered, reversible changes occurred in the nerves, either due to reversibly impaired sodium permeability or to an ischemic process related to the ultrafiltration dialysis.
Acute Disease↗
Serum lipids, lipoprotein analysis and apoprotein A-I, A-II and B levels in Friedreich's ataxia.
Serum lipid, lipoprotein and apoprotein parameters were evaluated in 15 patients (7 males and 8 females) with Friedreich's ataxia. Serum lipid levels in patients showed no significant differences compared to controls. Small reduction in serum phospholipid and in total HDL and HDL3 cholesterol levels were observed, and the female patients presented a slight reduced total cholesterol level; among the serum apoproteins, apo B was reduced only in the males. The most interesting findings concerned the lipoproteins, since both lipid and protein masses of the VLDL, LDL and HDL2 fractions were reduced. In reference to lipoprotein composition, however, HDL2 was the most modified fraction, showing an important protein reduction. From this point of view, this lipoprotein seems the most responsible for the changes observed in our patients. The meaning of this modified lipoprotein pattern in the pathophysiology of Friedreich's ataxia is not clear.
Adolescent↗
Fractures and osteoporosis.
The prevention of fractures in the elderly population has become a primary objective of public health because of the costs involved, in both economic and social terms. The present effective method for measuring bone mass has called attention to the relationship between osteoporosis and the risk of fracture. A reduction in bone mass is a determining factor, but not in itself sufficient for an overall understanding of the problem. This study collates anatomical, physiological, biomechanical and epidemiological data, which makes it possible to evaluate the different factors involved in predicting fractures in subjects affected with osteoporosis.
Age Factors↗
Quantification by dual photonabsorptiometry of local bone loss after fracture.
Total bone mineral and bone mineral density modifications were evaluated during fracture healing of long bones in patients with traumatic fractures of the lower limbs, using an experimental model based on the dual photonabsorptiometry technique. Seven patients (five males and two females; mean age, 19.5 years; range, 17-23 years) with tibia and fibula midshaft open fractures treated with osteosynthesis were studied. Dual energy gadolinium-153 photonabsorptiometry was used to measure distal leg bone loss at a skeletal segment distant from the fracture to exclude callus formation. Total bone mineral (TBM) and bone mineral density (BMD) of the tibia and fibula both in the fractured leg and in the healthy contralateral leg were measured on Days 10, 20, 30, 40, 60, and 120 after trauma. TBM and BMD of the healthy contralateral leg did not present any significant modifications at the different observation times. Both TBM and BMD of the fractured leg showed a progressive reduction that reached statistical significance starting on Day 30 with maximum reduction on Day 120 when TBM and BMD were reduced to almost one-half the initial value.
Absorptiometry, Photon↗
Zinc therapy in Wilson's disease: observations in five patients.
We report our experience with zinc (Zn) therapy in five patients with Wilson's disease (WD). In addition to neurologic examination, evaluation of Kayser-Fleischer rings and liver function tests, copper (Cu) and Zn concentrations in liver tissue, plasma, and urine were periodically evaluated by spectrophotometry. Many of the patients had had side effects due to penicillamine (PCA). Oral Zn sulphate (220 mg tid) reduced the WD symptoms and resulted in normal urinary Cu excretion in all five patients. One patient who had a transient gastric complaint during Zn administration, and in whom a decrease in liver Cu content was not observed, did not show any improvement in liver histology. He resumed PCA therapy after 29 months of Zn therapy. We conclude that long-term Zn treatment in Wilson's disease can be a safe and effective alternative to Cu chelating agents. However, patients should be periodically monitored for their Cu/Zn status to assess patient compliance with therapy.
Adolescent↗
Magnetic resonance imaging.
All of the data published in the literature show that MR is more sensitive than CT in diagnosing cerebral ischemic lesions. This greater sensitivity is due to its ability to detect even the minimal changes in tissue water content which occur in the early phases of the infarct. The literature concerning the use of MR in lacunar lesions is extremely limited but agrees with the general data regarding ischemia. However, there is some doubt that the thickness of the strata of CT and the interval between the strata of MR could have an influence on their ability to detect very small lesions. Modifications in the sensitivity of MR in detecting ischemic lesions are now well known: during the acute phase, the T2 images are more sensitive, while in the subacute and chronic phase both T1 and T2 have the same diagnostic capability.
Cerebral Infarction↗
Magnetic resonance imaging in the diagnosis of lesions of the central vestibular structures.
Explore the source record for details and available documents.
Adult↗
Spontaneous dorsal epidural haematoma: usefulness of magnetic resonance imaging and importance of operative treatment even in cases with complete paraplegia.
Spontaneous epidural haematomas are rare at any level of the spinal canal. The radiological diagnosis is usually made by myelography and in a few reported cases by computed tomography (CT). We describe a patient in which the final diagnosis was possible only with Magnetic Resonance Imaging (MRI). Surgical evacuation resulted in partial recovery of an already four days existing complete paraplegia. It is stressed that MRI is the most useful examination to differentiate haematomas from other spinal epidural lesions and that an operative evacuation of a spinal epidural haematoma is indicated even if the patient comes after a complete paraplegia has developed.
Aged↗