Hamartoma pulmonar de gran tamaño / Large size hamartoma of the lung

Resumen. Los hamartomas pulmonares son los tumores benignos más frecuentes del pulmón. Su tamaño suele oscilar de 1 a 2 centímetros habitualmente y se presentan clínicamente asintomáticos en su mayoría. Aportamos un caso de hamartoma pulmonar de gran tamaño, 9 cm de diámetro, en un paciente de 66 años, estudiado por edemas en miembros inferiores, sin manifestaciones clínicas pulmonares a pesar del tamaño tumoral. En la radiografía de tórax se apreció una masa con calcificaciones múltiples en su interior, en palomita de maíz. El diagnóstico se realizó con punción aspiración con aguja fina pulmonar. Se descartó la cirugía y el paciente permanece asintomático (AU)

Abstract. Pulmonary hamartomas are the most frequent benign tumors of the lung. Their size generally ranges from 1 to 2 centimeters and their presentation is mostly clinically asymptomatic. We present a case of large size hamartoma of the lung, of 9 cm in diameter, in a 66-year old male patient, studied due to edema in the lower limbs, without pulmonary clinical manifestations in spite of the tumor size. In the chest X-ray, a mass with multiple popcorn calcifications inside was visualized. The diagnosis was made through fine needle pulmonary aspiration puncture. Surgery was ruled out and the patient remains asymptomatic (AU)

Melanoma maligno pulmonar: ¿primario o metástasis única? / Pulmonary malignant melanoma: primary or single metastasis?

El melanoma maligno que afecta al sistema respiratorio tiene un origen casi siempre metastásico, mientras que los tumores primarios verdaderos son muy escasos. Son necesarios estudios clínicos y anatomopatológicos muy detallados para considerar que el pulmón es la localización primaria del melanoma. Se presenta el caso de una mujer de 82 años de edad con tos irritativa y un nódulo pulmonar periférico en la radiografía de tórax, diagnosticada de melanoma, sin lesiones cutáneas ni oculares previas. Se realizó tomografía por emisión de positrones fusionada con tomografía axial computarizada (PET-TAC) de cuerpo entero, apreciándose captación únicamente del nódulo pulmonar

The malignant melanoma that affects the respiratory system is almost always of metastatic origin, while true primary tumors are very scarce. Very detailed clinical and pathological studies are needed to consider that the lung is the primary site of the melanoma. We present the case of an 82-year-old woman with irritative cough and peripheral pulmonary nodule and the chest x-ray, diagnosed of melanoma, with no previous skin or eye lesions. Whole-body positron emission tomography fused with computed tomography (PET/CT) was performed, observing a single uptake of the pulmonary nodule (AU)

[Evolution of lung cancer in the North of the province of Castellón, Spain, 1993-2002]. / Evolución del carcinoma broncopulmonar en el norte de la provincia de Castellón, 1993-2002.

OBJECTIVE: To investigate the changes in lung cancer incidence, histological type, and survival in patients in the north of the province of Castellón, Spain, during a follow-up period of 10 years, and to compare the findings with other national and international studies. PATIENTS AND METHOD: All patients diagnosed with lung cancer between January 1, 1993 and December 31, 2002 were included in this prospective, observational study. Disease was confirmed by biopsy or suspected from clinical, radiological, and/or bronchoscopic findings. RESULTS: In the study period, 271 patients were diagnosed with lung cancer (239 men and 32 women), with a mean (SD) age of 66.8 (11.8) years. The age-adjusted incidence rate standardized to the world population was 20.42 cases per 100,000 population. Smokers or ex-smokers comprised 88.1% of the study population, and 72.6% of patients were over 60 years old. Biopsy confirmation was obtained in 262 cases (96.7%). Squamous cell carcinoma predominated (46.5%) but the proportion of adenocarcinoma increased (23.6%). Surgery was possible in only 22% of the patients. Mean overall 5-year survival was 15.7 months. CONCLUSIONS: In the north of the province of Castellón, the incidence of lung cancer continues to increase in men but has decreased slightly in women. Squamous cell carcinoma is the most common type, but the incidence of adenocarcinoma has clearly increased. Overall, survival did not improve during the 10 years of follow up despite advances in treatment.

[Epidemiological study of lung cancer in the northern part of the province of Castellón]. / Estudio epidemiológico del cáncer de pulmón en el norte de la provincia de Castellón.

OBJECTIVES: To estimate the incidence and survival of bronchopulmonary carcinoma in the northern part of the Spanish province of Castellón while collecting other epidemiologic data. PATIENTS AND METHODS: This prospective, observational study enrolled all patients residing habitually in northern Castellón with diagnoses of bronchopulmonary carcinoma recorded from 1 January 1993 until 31 December 1997. Enrollment criteria were cytohistologic confirmation of diagnosis or suspicion based on clinical, radiologic and/or bronchoscopic data. RESULTS: One hundred eighteen patients (100 men, 18 women) were so diagnosed, giving a world population-adjusted incidence of 17.4 cases per 100,000 inhabitants (men: 31.2; women: 4.5). Smokers or ex-smokers accounted for 84.7% and 74.5% were over 60 years of age. Cytohistologic confirmation was obtained for 117 patients (99%). Epidermoid carcinoma predominated (58%) and surgery was performed in only 23% of the cases. Only one patient was lost to follow-up during the study period. Mean 5-year survival was 7.6%. CONCLUSIONS: The standardized incidence of bronchopulmonary carcinoma in 1993-1997 in the northern part of Castellón was 17.4 cases per 100,000 inhabitants (women: 31.2; women: 4.5), with epidermoid carcinoma predominating and a five-year survival rate of 7.6%.

Estudio epidemiológico del cáncer de pulmón en el norte de la provincia de Castellón / Epidemiological study of lung cancer in the northern part of the province of Castellón (Spain)

OBJETIVOS: Conocer la incidencia y la supervivencia del carcinoma broncopulmonar en el norte de la provincia de Castellón, así como otros aspectos clinicoepidemiológicos. PACIENTES Y MÉTODOS: Se ha realizado un estudio prospectivo y observacional, en el que se incluyó a todos los pacientes diagnosticados de carcinoma broncopulmonar desde el 1 de enero de 1993 hasta el 31 de diciembre de 1997 que residían de forma habitual en esta zona. Se exigió la confirmación citohistológica o la sospecha basada en datos clínicos, radiológicos y/o broncoscópicos. RESULTADOS: Se diagnosticó a 118 pacientes, 100 varones y 18 mujeres. Esto supone una tasa de incidencia ajustada a la población mundial de 17,4 casos por 100.000 habitantes (varones: 31,2; mujeres: 4,5). En un 84,7 por ciento eran fumadores o ex fumadores, y el 74,5 por ciento de los pacientes tenía más de 60 años. Se obtuvo confirmación citohistológica en 117 casos (99 por ciento). Predominó el tipo epidermoide (58 por ciento), y sólo se pudo realizar tratamiento con cirugía en el 23 por ciento de los casos. Durante el período del estudio sólo se perdió el seguimiento de un paciente. La supervivencia media global a los 5 años ha sido del 7,6 por ciento. CONCLUSIONES: En el norte de la provincia de Castellón, la tasa de incidencia estandarizada del carcinoma broncopulmonar en el período 1993-1997 ha sido de 17,4 casos por 100.000 habitantes (varones 31,2; mujeres: 4,5), predomina el tipo epidermoide y la supervivencia a los 5 años es del 7,6 por ciento (AU)

Risk factors for hip fracture in men from southern Europe: the MEDOS study. Mediterranean Osteoporosis Study.

The aims of this study were to identify risk factors for hip fracture in men aged 50 years or more. We identified 730 men with hip fracture from 14 centers from Portugal, Spain, France, Italy, Greece and Turkey during the course of a prospective study of hip fracture incidence and 1132 age-stratified controls selected from the neighborhood or population registers. The questionnaire examined aspects of work, physical activity past and present, diseases and drugs, height, weight, indices of co-morbidity and consumption of tobacco, alcohol, calcium, coffee and tea. Significant risk factors identified by univariate analysis included low body mass index (BMI), low sunlight exposure, a low degree of recreational physical activity, low consumption of milk and cheese, and a poor mental score. Co-morbidity including sleep disturbances, loss of weight, impaired mental status and poor appetite were also significant risk factors. Previous stroke with hemiplegia, prior fragility fractures, senile dementia, alcoholism and gastrectomy were associated with significant risk, whereas osteoarthrosis, nephrolithiasis and myocardial infarction were associated with lower risks. Taking medications was not associated with a difference in risk apart from a protective effect with the use of analgesics independent of co-existing osteoarthrosis and an increased risk with the use of anti-epileptic agents. Of the potentially 'reversible' risk factors, BMI, leisure exercise, exposure to sunlight and consumption of tea and alcohol and tobacco remained independent risk factors after multivariate analysis, accounting for 54% of hip fractures. Excluding BMI, 46% of fractures could be explained on the basis of the risk factors sought. Of the remaining factors low exposure to sunlight and decreased physical activity accounted for the highest attributable risks (14% and 9% respectively). The use of risk factors to predict hip fractures had relatively low sensitivity and specificity (59.6% and 61.0% respectively). We conclude that lifestyle factors are associated with significant differences in the risk of hip fracture. Potentially remediable factors including a low degree of physical exercise and a low BMI account for a large component of the total risk.

Static lung volumes: reference values from a Latin population of Spanish descent.

BACKGROUND AND OBJECTIVES: The aim of this study was to develop a set of prediction equations and 90% confidence intervals for static lung volumes using the multibreath helium equilibration method from a sample of asymptomatic Caucasian subjects of Spanish descent. Moreover, these equations were compared with those of previous studies. METHODS: Measurements of static lung volumes using techniques recommended by the American Thoracic Society and the European Community for Steel and Coal were carried out on a selected sample of 591 healthy nonsmoking volunteers (305 men and 286 women) aged 18-88 years, living in the metropolitan area of Valencia, on the east coast of Spain. Multiple regression analysis using height, age and weight as independent variables were used to provide predicted values for both sexes. These reference values were compared with other sets of prediction equations reported in the literature using an independent sample of 69 subjects (32 men and 37 women). RESULTS: Simple linear regression equations using age, height and body weight predicted all the subdivisions of lung volumes (vital capacity, expiratory reserve volume (ERV), inspiratory capacity, functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), FRC/TLC and RV/TLC) as well as more complex equational models. The distribution of residuals fulfilled the assumptions of multiple regression analysis (independence, homoscedasticity and Gaussian distribution of residuals), except for ERV, using simple linear models. The derived equations did not differ significantly from most of the previously reported equations and were usually superior in their ability to predict the lung volumes. CONCLUSIONS: The use of the present prediction equations is recommended in the Latin population of Spanish descent and in populations with similar Caucasian characteristics.

Increased proliferation of osteoblast precursor cells in estrogen-deficient rats.

We have evaluated the in vivo and in vitro changes in osteoblast characteristics induced by estrogen deficiency and 17 beta-estradiol (E2) treatment in ovariectomized (OVX) rats. Estrogen deficiency induced osteopenia and increased bone turnover, as evidenced by bone histomorphometry at 1, 3, and 6 mo postovariectomy. Bone surface osteoblastic cells (OB) isolated from tibias of OVX rats, OVX rats treated with E2 (10 micrograms/kg body wt), and sham rats showed no difference in alkaline phosphatase activity and osteocalcin production in vitro. In contrast the proliferation rate of OB cells was higher in OVX rats compared with sham rats at all time points post-surgery, as shown by [3H]thymidine incorporation and cell number. The proliferation rate of alkaline phosphatase-positive marrow cells was also higher in OVX rats compared with sham rats. E2 treatment of OVX rats corrected histologic indexes of bone resorption and formation and normalized OB cell proliferation. induced by estrogen deficiency in OVX rats is related to an increased proliferation of osteoblast precursor cells present in the marrow stroma and along the endosteal bone surface.

Residential care and risk of proximal femur fracture.

The risk of hip fracture is higher among persons living in long-term care than among persons living at home. The aim of this study was to explain the difference in risk between the two types of residence by identifying differences in the respective risk factor profiles. Information from the Mediterranean osteoporosis (MEDOS) study questionnaire was used for statistical analyses of 107 non-demented female cases and 225 neighbourhood controls matched for age, sex, and residential area. The statistical analyses incorporated adjustments of the risk estimates by unconditional multivariate logistic regression. Urban background, activity, and morbidity were found to differ between the two types of residence. The detected differences in risk factor profiles were, however, not considered to be sufficient as an explanation for the difference in risk of fracture.

[Vitamin-resistant hypophosphatemic rickets and spinal cord compression. Apropos of 2 cases]. / Rachitisme vitamino-résistant hypo-phosphatémique et compression médullaire. A propos de deux cas.

Adults with X-linked vitamin-resistant hypophosphatemic rickets can develop spinal cord compression as a result of spinal canal stenosis due to involvement of the spine with the increased periosteal and ligamentary calcification which is typical of the disease. Two cases are reported. In both patients, spinal cord compression manifested as rapidly progressive spastic paraplegia due to compression at T9 and T5, respectively. Decompressive laminectomy ensured full recovery in one case but was ineffective in the other. In both cases, paraplegia developed approximately one year after initiation of therapy combining a metabolite of vitamin D and phosphorus in high doses. Current imaging techniques (CT scan, magnetic resonance imaging) provide highly accurate information on the anatomic mechanism of the stenosis, its often multiple locations, and its course. Three factors are involved in the stenosis, in variable degrees: thickening of the laminae, hypertrophy of the facet joints, thickening and calcification of the yellow ligament. Magnetic resonance imaging is the investigation of choice in these patients. A deleterious effect vitamin D-phosphorus treatment cannot be outruled. The appropriateness of initiating this treatment should be prudently discussed and treated patients should be closely monitored.

Evidence for efficacy of drugs affecting bone metabolism in preventing hip fracture.

OBJECTIVE: To examine the effects of taking drugs affecting bone metabolism on the risk of hip fracture in women aged over 50 years. DESIGN: Retrospective, population based, case-control study by questionnaire. SETTING: 14 centres in six countries in southern Europe. SUBJECTS: 2086 women with hip fracture and 3532 control women matched for age. MAIN OUTCOME MEASURES: Number of drugs affecting bone metabolism taken and length taken for. RESULTS: Women taking drugs affecting bone metabolism had a significantly decreased risk of hip fracture. After adjustment for differences in other risk factors, the relative risk of hip fractures was 0.55 (95% confidence interval 0.31 to 0.85) in women taking oestrogens, 0.75 (0.60 to 0.94) in those taking calcium, and 0.69 (0.51 to 0.92) in those taking calcitonin. The fall in risk was not significant for anabolic steroids (0.6 (0.29 to 1.22)). Neither vitamin D nor fluorides were associated with a significant decrease in the risk of hip fracture. The effect on hip fracture risk increased significantly with increasing duration of exposure (risk ratio 0.8 (0.61 to 1.05) for less than median exposure v 0.66 (0.5 to 0.88) for greater than median exposure). Drugs were equally effective in older and younger women, with the exception of oestrogen. CONCLUSIONS: Oestrogen, calcium, and calcitonins significantly decrease the risk of hip fracture. Short term intervention late in the natural course of osteoporosis may have significant effects on the incidence of hip fracture.

Dynamics of circulating osteocalcin in rats during growth and under experimental conditions.

Osteocalcin is the most abundant non-collagenous protein produced in the process of bone formation. A specific radioimmunoassay has been developed using a rabbit antiserum raised against osteocalcin extracted from rat bone. The sensitivity of the assay was tested in male and female rats under different experimental conditions: ovariectomy led to a mild increase in circulating osteocalcin (70.6 +/- 6.9 vs 51.6 +/- 6.3 ng/ml; p < 0.05) and deprivation of dietary calcium elevated plasma levels further (119 +/- 6.3 ng/ml; p < 0.01). As expected, pharmacological enhancement of bone turnover with calcitriol produced a significant increase in plasma osteocalcin (296 +/- 24.1 vs 89.5 +/- 5.1 ng/ml; p < 0.01), whereas prednisolone, a steroidal compound known to inhibit osteoid mineralization, significantly reduced circulating concentrations of this protein (70 +/- 7.4 vs 100 +/- 6.3 ng/ml; p < 0.05). Plasma kinetics recorded in female rats between birth and the 100th week revealed a highly significant (p < 0.001) elevation peaking at the third week (231 +/- 70.6 ng/ml) and slowly declining to reach values measured at birth (41.3 +/- 9.2 ng/ml) at the 16th week (47 +/- 4.6 ng/ml). Subsequently, a small but significant (p < 0.05) decline towards senescence was recorded. The osteocalcin surge preceded the period of rapid growth (weeks 3 to 11) estimated by vertebral length progression, showing a tendency to stabilize as growth spurt slowed down. A moderate but significant (p < 0.01) increment was observed after mating (87.8 +/- 5.1 vs 69.5 +/- 4.0 ng/ml). Although plasma osteocalcin remained stable during lactation, average levels were elevated in comparison with age-matched non-pregnant controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of fluoride on bone and bone cells in ovariectomized rats.

To evaluate whether treatment with a mitogenic agent may increase bone formation and bone mass in osteopenia induced by estrogen deficiency, we determined the effect of oral fluoride treatment on bone and bone cells in ovariectomized rats. Sodium fluoride (NaF) was administered to 3-month-old ovariectomized rats 1 day after ovariectomy (OVX) for 1, 3, and 6 months. NaF was given in drinking water at the dose of 1 mg/kg body weight per day. Fluoride administration led to a partial prevention of the bone loss induced by OVX as shown by histologic analysis of tibial metaphysis and by evaluation of femoral calcium content. These beneficial effects of fluoride were more striking at early time points (1 and 3 months postovariectomy) than after 6 months of treatment. The increase in trabecular bone volume in OVX rats treated with fluoride was associated with a rise in the osteoblast surface, which was increased by 60, 72, and 235% at 1, 3, and 6 months postovariectomy compared to untreated OVX rats. In OVX rats and in sham-operated rats plasma osteocalcin was increased in correlation with the osteoblast surface. However, these two parameters were not correlated in OVX rats treated with fluoride. The heat-labile bone-specific alkaline phosphatase in plasma was decreased in OVX rats treated with fluoride compared to OVX rats, suggesting that both the number and the activity of osteoblasts were affected by NaF treatment. To examine the effect of fluoride on the osteocalcin production and the proliferative capacity of bone cells, osteoblastic cells were isolated by collagenase digestion from the bone surface of tibia in treated and untreated OVX rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Agenesis of the right pulmonary artery in a young asymptomatic girl.

We report the case of a 13 yr old, asymptomatic girl with agenesis of the right pulmonary artery. In the context of a tuberculosis survey in her school, an X-ray examination disclosed a decreased volume of the right lung. Ventilation and perfusion scans and digital substraction angiography established the diagnosis.

Calcemic response to magnesium or 1-alpha-hydroxycholecalciferol treatment in intestinal hypomagnesemia.

The mechanism of hypocalcemia was assessed prospectively in 10 gastroenterological hypomagnesemic patients. Baseline serum magnesium was 0.9 +/- 0.1 mg/dl and calcium, 7.2 +/- 0.4 md/dl. Plasma 25-hydroxyvitamin D (25 (OH)D) was low in 5 patients and normal in the others. Plasma parathormone (PTH) and urinary cyclic AMP (ur. cAMP), although twofold above normal values, were inappropriately low and increased sharply after a magnesium bolus injection. There was no renal resistance to PTH as ur. cAMP increased after i.v. bovine PTH bolus injection. Subsequently, patients were randomly divided into 2 groups, each including patients with low or normal levels of 25 (OH)D, receiving either MgCl2 (group I) or 1 microgram/d of 1-alpha (OH)D (group II) for one week. Although magnesium status remained low in group II patients, increase in plasma calcium was identical in both groups. Serum calcium levels in patients receiving combined 1-alpha (OH)D and MgCl2 during a second week of treatment returned to normal. In the 4 tested patients, plasma 1,25 (OH)2D levels were low before, but also after correction of hypomagnesemia, suggesting that low level of 1,25 (OH)2D might not be due to hypomagnesemia. Therefore, treatment with low dosage of 1-alpha (OH)2D associated with magnesium chloride repletion can be recommended to restore normal calcium homeostasis in patients with intestinal hypomagnesemia.

Stress fractures of the lower limbs in osteoporotic patients treated with fluoride.

We report clinical and bone morphometric findings in 18 osteoporotic patients who experienced stress fractures during fluoride therapy. Patients were treated with either sodium fluoride (n = 15), or sodium monofluorophosphate (n = 3). Oral calcium supplementation was given in 11 patients, and vitamin D in 13. Stress fractures occurred after 17.1 +/- 10.3 months of therapy (range: 5-41 months). Atraumatic sudden pain in a lower limb bone extremity, normal initial roentgenogram, high 99technetium uptake on early bone scan, and a 3 to 4 week delay in linear bone condensation area at the same site were characteristics of stress fracture. The most frequent sites were the tibial metaphysis (n = 13), femoral neck (n = 10), and calcaneus (n = 4). Biochemical data showed increased plasma alkaline phosphatase levels in 11 patients, and mild renal failure in 2. Bone histomorphometry was performed on an iliac crest specimen in 10 patients at the time of the stress fracture. Trabecular bone volume was normal, and formation parameters were increased. Features of osteomalacia were encountered in only 2 patients with decreased renal function. Trabecular resorption was increased, as assessed by the osteoclastic surface (1.01 +/- 1.15% bone surface), and the number of osteoclasts (0.44 +/- 0.49 per mm2 bone section). The clinical course was favorable in all patients who stopped fluoride, although 5 patients who continued the treatment had either completion of femoral neck stress fractures to hip fractures (n = 2), or recurrent stress fractures (n = 2), or both (n = 1). Fluoride appears to be a key factor in the pathogenesis of stress fractures, and may be associated with increased trabecular resorption in some treated patients.

Comparative effects of a novel vitamin D analogue MC-903 and 1,25-dihydroxyvitamin D3 on alkaline phosphatase activity, osteocalcin and DNA synthesis by human osteoblastic cells in culture.

MC-903 is a novel vitamin D analogue which has been shown to promote epidermal cell differentiation but is 100 times less active than 1,25 dihydroxyvitamin D3 (1,25(OH)2D) in causing hypercalcemia. In order to determine the activity of this compound on bone cells, we have compared the effects of MC-903 and 1,25 dihydroxyvitamin D3 (1,25(OH)2D) on parameters of cell proliferation and differentiation in cultured normal human osteoblastic cells derived by migration from trabecular bone fragments. Dose response curves showed that MC-903 was 10 to 100 times less effective than 1,25(OH)2D in stimulating the synthesis of the osteoblast specific protein osteocalcin by human bone cells depending on the basal osteocalcin production. In cells showing high basal osteocalcin synthesis, 1,25(OH)2D (10(-8) M) was 2- to 3-fold more potent than MC-903 (10(-8) M) in inducing osteocalcin from 48 to 96 h of treatment. The greater activity of 1,25(OH)2D over MC-903 was observed in human bone cell cultures with elevated basal osteocalcin levels, indicating that the response to 1,25(OH)2D but not to MC-903 was amplified in cells with the higher osteoblastic characteristics. The effects of MC-903 and 1,25(OH)2D on alkaline phosphatase activity were not markedly different. Transforming Growth Factor-beta (TGF beta) (0.5 ng/mL, 48 h) was found to completely suppress the osteocalcin synthesis induced by 1,25(OH)2D (10(-8) and 10(-9) M), whereas the MC-903-induced osteocalcin synthesis was not affected, suggesting a negative interaction between TGF beta and 1,25(OH)2D but not MC-903 on osteocalcin synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of calcitonin administration on young pig trabecular bone remodeling.

Ten-week-old pigs were treated with 4 different treatment schedules of porcine calcitonin for 2 months. Groups C1 and C4 received continuous treatment: C1 had daily IM injections (4 IU/kg/BW (body weight) each injection), and C4 was infused with a minipump implanted subcutaneously delivering 4 IU/kg/BW/day. Groups C2 and C3 received intermittent calcitonin treatment (each injection 4 IU/kg/BW): C2 was given 1 out of every four days, C3 was injected 5 consecutive days out of 20 days. The total dosage received in C1 versus C4 and C2 versus C3 were the same. Results were evaluated by histomorphometry after double tetracycline labeling on iliac trabecular bone. Resorption surfaces were decreased in groups C2, C3 and C4, but bone volume, osteoclast surfaces, and interstitial bone thickness were not modified in any group receiving calcitonin. Osteoblast and mineralizing surfaces were increased in group C2, C3 and C4. Plasma 1,25-dihydroxyvitamin D concentration and bone formation rate were increased in groups C2 and C4. Plasma immunoreactive parathyroid hormone levels and parathyroid weights were not increased in any treated groups. In conclusion, 2-month calcitonin treatment did not decrease the amount of bone resorbed in growing pigs. Continuous calcitonin infusion and intermittent calcitonin administration induced an increase in the extent of active bone formation which might be in part dependent on an increased production of 1,25 dihydroxyvitamin D.

Cyclosporin A induces in vivo inhibition of resorption and stimulation of formation in rat bone.

We investigated a possible "in vivo" effect of cyclosporin A, an immunosuppressive agent, on normal rat bone remodeling. At an oral daily dose of 7 mg/kg for 14 days, the blood level of cyclosporin A was in the usual effective range and no change in renal function or magnesium metabolism was observed. Treated rats had decreased bone resorption: urinary hydroxyproline, plasma acid phosphatase, and the number of osteoclasts in caudal vertebrae were significantly reduced. By contrast, bone formation assessed by dynamic histomorphometry after double tetracycline labeling was increased. No modification of calciotropic hormones (vitamin D metabolites and parathyroid hormone as assessed by urinary cyclic AMP) was observed at the end of the treatment. These results suggest that in vivo cyclosporin A treatment induces bone remodeling modifications related to either a direct or a lymphokine-mediated effect on bone cells.