Assessment of skeletal status in patients with congenital disorder of glycosylation type IA

Congenital disorder of glycosylation (CDG) type IA (phosphomannomutase deficiency) is the most common of a group of inherited metabolic disorders that are due to defective glycosylation of glycoproteins. CDG-IA is clinically characterized by major nervous system involvement and various organs are affected to a variable degree. Common clinical findings are skeletal changes including peculiar thoracic deformity and joint restriction, while a major radiological feature is diffuse osteopenia. The aim of this study was to measure bone density and biochemical markers of bone turnover in three patients with CDG-IA, whose age ranged between 14 and 27 years. We found that bone mass, as judged by standard densitometry, quantitative computed tomography and ultrasonography, was lower in patients than in age- and sex-matched healthy controls. Biochemical indexes of bone resorption including free pyridinoline levels in serum and pyridinoline and deoxypyridinoline urinary excretions were normal, whereas bone formation markers (serum osteocalcin and serum bone-specific alkaline phosphatase) activity were increased. These results suggest that low bone density is a component of CDG-IA, which should be considered among inherited metabolic diseases with decreased bone mass. We hypothesize that hypoglycosylation of noncollagenous bone proteins may contribute to the osteopenia observed in these patients. From a clinical point of view, our observation shows that bone density measurements can provide a quantitative assessment of bone involvement in such diseases.

Exaggerated endothelin release in response to acute mental stress in patients with intermittent claudication

Endothelin-1 (ET-1) is an endothelial-derived 21-amino-acid peptide with potent vasoconstrictor and mitogenic properties implicated in several cardiovascular disorders. To evaluate the plasma ET-1 response to mental stress in patients with intermittent claudication, plasma endothelin concentrations were measured by radioimmunoassay in 15 claudicant outpatients (13 men and 2 women; mean age 62 +/- 4 years) and in 15 sex- and age-matched healthy control subjects (12 men and 3 women; mean age 60 +/- 8 years) before and after mental arithmetic performed for 10 minutes. Venous blood samples were drawn from an antecubital vein at baseline, at the end of the mental arithmetic, and at 10 minutes of recovery. Baseline ET-1 values were higher in patients with intermittent claudication as compared with control subjects (4.5 +/- 0.5 pmol/L and 2.2 +/- 0.3 pmol/L, respectively, p < 0.0001). At the end of mental stress, ET-1 levels rose significantly in both groups from baseline (p < 0.001) reaching a higher value in patients with intermittent claudication than in control subjects (5.6 +/- 0.7 pmol/L and 2.4 +/- 0.4 pmol/L, respectively, p < 0.0001). The percent increases (delta%) in ET-1 plasma concentrations from baseline in response to mental stress were significantly greater in claudicant patients than in control subjects (+23 +/- 9% and +9 +/- 7%, respectively, p < 0.0001). ET-1 plasma concentrations returned to baseline values similarly in both groups at minute 10 of the recovery period. These findings show that acute mental stress causes an exaggerated release of ET-1 in patients with intermittent claudication and suggest that this could be a potential pathophysiological mechanism through which mental stress may trigger adverse acute cardiac events and accelerate progression of atherosclerosis in these patients.

Bone ultrasonometry, bone density, and turnover markers in type 1 Gaucher disease

In 12 patients (mean age, 33 +/- 13 years) with type 1 Gaucher disease (GD), we evaluated bone mass by broadband ultrasound attenuation (BUA) of the calcaneus and dual X-ray absorptiometry (DXA) of the total body, lumbar spine, and hip. In all patients, we measured serum levels of osteocalcin (OC) and bone-specific alkaline phosphatase (BAP) and urinary excretion of pyridinoline (Pyr/Cr) and deoxypyridinoline (D-Pyr/Cr) cross-links. Compared to age- and sex-matched healthy controls, patients with GD showed marked osteopenia at all measuring sites as expected. Values of BUA (67.25 +/- 15.83 dB/MHz) were also significantly reduced. OC and BAP concentrations were within the normal range. Pyr/Cr and D-Pyr/Cr were significantly higher than in controls. Calculating T- and Z scores, we found a significant correlation between the Bone Severity Score Index (BSSI) and both BUA and BMD measurements. A significant correlation was also found between pyridinoline urinary excretion and both BSSI and BUA at the calcaneus. Our data suggest that type 1 GD in adulthood is associated with increased bone resorption and that BUA at the calcaneus may be a relevant tool in the assessment of bone status in these patients.

Response of biochemical markers of bone turnover to estrogen treatment in post-menopausal women: evidence against an early anabolic effect on bone formation

Bone loss following menopause can be prevented or reduced by estrogen replacement therapy (ERT). The primary action of estrogen on bone is generally considered to be antiresorptive, but some evidence would also suggest a stimulatory effect on bone formation. The aim of this study was to assess the effect of ERT on biochemical markers of bone resorption (urinary pyridinoline and deoxypyridinoline), and of bone formation (bone-specific alkaline phosphatase--B-ALP, and the C-terminal propeptide of type I collagen--CICP) in a group of 25 postmenopausal women with no evidence of osteoporosis. Since the suggested anabolic effect of estrogen seems to take place in the early period of ERT, we measured the response of markers immediately before and after the start of treatment (30, 60, 120 and 180 days). The markers of bone resorption started to decrease at 30 days and remained low thereafter. We also observed a similar decrease in serum levels of B-ALP and CICP, reflecting a reduction of bone formation rate. Our data would indicate that ERT at the given dose does not have early anabolic effects on bone, in addition to its recognized suppressive effect on bone resorption.

Role of soy diet and L-arginine in cyclosporin-A-induced osteopenia in rats

Our previous studies show that chronic administration of L-arginine decreases cyclosporin-A-induced bone loss. The present study was designed to investigate whether a soy diet could prevent cyclosporin A-induced osteopenia and eventually improve the protective effect of L-arginine. Rats on soy diet were treated with cyclosporin-A, L-arginine, cyclosporin-A + L-arginine or saline. Control groups received a normal diet and the same pharmacological treatment. Our results show that a soy diet prevents osteopenia only in the spinal cord (+30%) and confirm the protective effect of L-arginine in cyclosporin-A-induced osteopenia in whole body, pelvis and spine of rats on a normal diet (+31%, +55%, +55%, respectively). Moreover these data show that the osteoprotective effect of L-arginine in the whole body, pelvis and spine improves in the case of soy diet (+60%, +72%, +89%, respectively). The results suggest that a soy diet exerts a positive effect in cyclosporin-A-induced osteopenia only in sites with high turn-over and improves the osteoprotective effect of L-arginine.

L-arginine prevents bone loss and bone collagen breakdown in cyclosporin A-treated rats

Cyclosporin A is implicated in the pathogenesis of post-transplantation bone disease. Because of recent evidence that cyclosporin A may cause renal and cardiovascular toxicity by inhibiting nitric oxide (NO) activity, and that NO slows bone remodeling and bone loss in animal and human studies, we investigated a possible link between NO production and beneficial effects on bone health in cyclosporin A-treated rats. Thirty-six 10-week-old male rats were assigned to six groups of six animals each, and treated for 4 weeks with: vehicle; cyclosporin A; L-arginine; N(G)-nitro-L-arginine methylester (L-NAME, a general inhibitor of NO synthase activity); a combination of cyclosporin A+L-arginine; and a combination of cyclosporin A+L-NAME. Whole body and regional (spine and pelvis) bone mineral content of rats were measured under basal conditions and at the end of the treatment period by dual-energy X-ray absorptiometry (DXA) scanning. Femur weights and serum concentrations of pyridinoline, a reliable marker of bone resorption, were measured at the end of the study period. Cyclosporin A-, L-NAME-, and cyclosporin A+L-NAME-treated rats had significantly lower bone mineral content and femur weights, and significantly higher pyridinoline levels than did control animals. The administration of L-arginine appeared to prevent bone loss caused by cyclosporin A, suggesting that this amino acid, which can be converted to produce NO, might prove useful in preventing disturbed bone modeling and inhibition of bone growth associated with cyclosporin A therapy.

Correlation of quantitative ultrasound of bone with biochemical markers of bone resorption in women with osteoporotic fractures

The purpose of this study was to examine the correlation of parameters of bone quality assessed by quantitative ultrasound (QUS) with biochemical indexes of bone resorption. QUS of the calcaneus and the hand phalanges, and biochemical parameters (urinary excretion of pyridinoline [Pyr] and deoxypyridinoline [D-Pyr]) were measured in a group of 30 well-characterized postmenopausal women with established osteoporosis and fragility fractures. All patients were treatment free. QUS data significantly correlated with both urinary Pyr and D-Pyr (p < 0.001 for speed of sound [SOS], broadband ultrasound attenuation [BUA], and stiffness at the heel; p < 0.001 for amplitude-dependent SOS at the proximal phalanges of the nondominant hand). No significant correlation was observed between spine and femoral bone mineral density and the urinary excretion of Pyr and D-Pyr. Results of this study suggest that QUS of bone evaluates characteristics of bone influenced by the bone resorption rate.

Immobilization-dependent bone collagen breakdown appears to increase with time: evidence for a lack of new bone equilibrium in response to reduced load during prolonged bed rest

The purpose of this study was to evaluate the effect of prolonged immobilization on bone, in order to investigate how skeletal turnover adapts to bed rest. We examined indices of bone formation and bone resorption in the serum and urine of fifty-four patients (26 males and 28 females) immobilized after an episode of paralytic stroke. The length of immobilization ranged from 30 to 180 days. A significant, time-dependent increase in markers of resorption - urinary pyridinoline (Pyr) and deoxypyridinoline (D-Pyr), serum Type I collagen cross-linked C-telopeptide (ICTP) - was observed in immobilized patients, as compared to free-living healthy subjects. The positive correlation between resorption markers increase and the length of immobilization suggests that the rate of bone resorption did not decrease with time. On the other hand, the levels of markers of bone formation - bone-specific alkaline phosphatase (B-ALP), and the carboxyl-terminal propeptide of Type I procollagen (PICP) - remained within the normal range in all patients, regardless the length of immobilization. Our results would indicate an uncoupling between bone formation and bone resorption during bed rest, and suggest that the bone collagen break-down was not a self-limiting process in immobilized patients, and that a new equilibrium or "steady state" in response to the reduced load was not reached in the skeleton.

[The immediate and midterm results of percutaneous mitral valvuloplasty in subjects over 60]

We have analyzed the immediate and mid-term (1 and 2 years) results of percutaneous mitral valvuloplasty (PMV) by Inoue's catheter in 97 patients < 60 years (Group A) compared with 34 patients > 60 years (Group B). In 61% Group A the patients were in NYHA functional class II, 36% in III, and 3% in I; in Group B, 56% of the patients were in NYHA functional class III, 38% in II, and 6% in IV. Mean mitral valve area was 1.1 cm2 before dilatation in both groups, and a significant (p < 0.0001) increase was obtained in both Group A (0.9 +/- 0.3 cm2) and Group B (0.8 +/- 0.3 cm2). No significant differences were observed between the two groups. Mean transvalvular gradient decreased significantly (p < 0.0001) from 13.6 +/- 5.7 to 7.2 +/- 3.1 mmHg in Group A, and from 9.9 +/- 4 to 6.5 +/- 2.3 mmHg in Group B (A vs B: p < 0.02). Optimal result was obtained in 94% and 88% of Group A and Group B patients, respectively. Suboptimal result was obtained in 2% and 6% of Group A and Group B patients, respectively. These differences were not significant. Failure of PMV occurred in 4% and 6%, respectively. At 1-year follow-up Group A 7 patients and 5 Group B patients showed restenosis; at 2-year follow-up one more restenosis was present in Group A (A vs B at 1 and 2 years: NS). We conclude that PMV is a safe and effective technique in young patients and in patients > 60 years.

[Percutaneous mitral valvuloplasty in patients who have undergone surgical commissurotomy]

Percutaneous mitral valvuloplasty (PMV) was performed with Inoue's catheter, by anterograde approach, in 19 patients (2 males and 17 females, mean age of 56 +/- 13 years) with restenosis after surgical commissurotomy. Mean valvular area increased from 1.2 +/- 0.2 to 1.9 +/- 0.2 cm2 while mean transvalvular gradient decreased from 13 +/- 6 to 7 +/- 4 mmHg. All but 2 patients reached optimal results; one had a suboptimal result (final valvular area > 1.5 cm2, percentage of increase less than 25%), and 1 was sent to the surgeon for a significant increase in mitral regurgitation ( ). At 1 year follow-up, (available for 11 patients), mean valvular area was 1.7 +/- 0.3 cm2 and transmitral gradient was of 5.4 +/- 2 mmHg. Four patients showed a restenosis; 1 of them underwent surgical mitral valve replacement after a second unsuccessful PMV; 2 showed good clinical conditions, while the fourth patient was sent to the surgeon for the high echocardiographic score. At 2-year follow-up, available for 4 patients, the mean gradient was of 5.5 +/- 2.5 mmHg and the mitral valve area was 1.8 +/- 0.2 cm2. NYHA functional class progressively improved after the procedure in all patients but those undergoing mitral valve replacement. In conclusion, despite the occurrence of restenosis, PMV seems to be feasible in patients who already underwent surgical commissurotomy; this procedure can avoid the risks of a second surgery, and should be considered the first choice treatment in these patients.

Body composition and bone mineral density in competitive athletes in different sports

Bone mineral density (BMD) of the vertebral spine, appendicular skeleton, and whole body was studied in male athletes who chronically trained by different forms of skeletal loading. Eighteen subjects performed weight-bearing activity (canoeists, n = 18), and 14 performed non-weight-bearing activity (cyclists, n = 14). Twenty-eight age-matched male students served as non-athletic controls. The canoeists had significantly higher spine, pelvic and total body BMD than cyclists and controls. No intergroup difference was observed in the BMD of arms and legs despite the fact that physical activity of canoeists and cyclists were characterized by forceful muscular contractions. It is concluded that weight-bearing activity is essential to obtain beneficial skeletal effects on total and regional bone mass in young subjects.

Anti-inflammatory activity of amylin and CGRP in different experimental models of inflammation

The anti-inflammatory activity of amylin was studied in different models of inflammation, and compared to that of CGRP. Both peptides were active against mouse ear oedema induced by croton oil and acetic acid-induced peritonitis in the rat. CGRP was more potent than amylin in both models. Pretreatment with CGRP 8-37 fragment blocked the anti-inflammatory activity of both peptides in croton oil ear oedema. No anti-inflammatory activity was evidenced against serotonin-induced rat paw oedema and plasma protein extravasation induced by dextran in rat skin. Our results suggest that amylin exerts anti-inflammatory activity only in inflammatory models characterized by a vascular component. This effect appears to be mediated by the involvement of CGRP receptors.

[Modification of cortical and trabecular mineral density of the femur, induced by ipriflavone therapy, Clinical results after 12 months]

In order to evaluate the effects of ipriflavone therapy, a clinical and metabolic study was carried out in a group of female patients with low bone mass. In particular, mineral density of the proximal femur was measured, this being a fundamental factor for the resistance of this district. At the end of the 12-months treatment cycle, reduced plasma concentration of Bone Gla Protein and urinary hydroxyproline/creatinine ratio (indicating reduced bone resorption), and a significant increase of bone density of the femoral neck and of the trabecular substructure of Ward's triangle were found. On the whole, treatment was well tolerated.

A role for nitric oxide in the anti-ulcer activity of calcitonin gene-related peptide

The anti-ulcer activity of calcitonin gene-related peptide (CGRP) was inhibited, in a dose-dependent manner, by pretreatment with NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthase. Our results suggest that endogenous nitric oxide is involved in the anti-ulcer activity of CGRP.

Differences in the time course of the effects of oophorectomy in women on parameters of bone metabolism and interleukin-1 levels in the circulation

Interleukin-1 is a cytokine with bone-resorbing activity which is claimed to play a role in the pathogenesis of osteoporosis and of post-oophorectomy bone loss. We measured plasma levels of interleukin-1 (IL-1) in 16 women who underwent hysterectomy and bilateral oophorectomy and in 12 women with hysterectomy alone before surgery and 7, 15, 30, 45 and 60 days after surgery. Only oophorectomized patients showed a significant increase of circulating interleukin-1 levels. This increase was significant only 30 days after surgery, whereas a rise at 7 days (P < 0.001) was observed for serum calcium and hydroxyproline/creatinine and calcium/creatinine ratios. These data do not indicate a definite role of IL-1 in promoting bone resorption in estrogen-deficient women in vivo.

Effects of calcitonin gene-related peptide on extrapyramidal motor system

The effects of central administration of calcitonin gene-related peptide (CGRP, 1 or 100 ng/rat) on behavioral and biochemical parameters related to the extrapyramidal motor system were investigated in male rats. The peptide-induced catalepsy occurred only at the dose of 100 ng/rat and hypomotility at both doses used. Calcitonin gene-related peptide increased haloperidol-induced catalepsy and decreased apomorphine-induced hypermotility at the doses of 1 and 100 ng/rat. Although these behaviors are related to dopamine, no significant change of striatal DA or DOPAC concentration were observed after central administration of the peptide. Other neurotransmitters may be directly or indirectly involved in these behavioral effects of CGRP.

Parathyroid hormone fragment 1-34 and anti-inflammatory effect

We have studied the possible activity of the rat parathyroid hormone fragment 1-34, peripherally or centrally injected, on the vascular permeability induced by local administration of croton oil. Our study considered also the possible interference of parathyroid hormone fragment 1-34 on the release of histamine by mast cells and on the content of histamine in paw tissue. Parathyroid hormone fragment 1-34 significantly reduced the increase in vascular permeability produced in mice by local croton oil injection, as well as the serotonin-induced paw edema in the rat. These effects of parathyroid hormone fragment 1-34 were present only after peripheral administration. At the dose of 3.3 micrograms/kg, it decreased the histamine content in paw tissue. Peripheral administration of a calcium antagonist, such as nimodipine, at the dose of 50 micrograms/kg, or a metal-chelating agent, such as ethylene-diaminetetraacetic acid, at the dose of 10 micrograms/kg, antagonized the anti-inflammatory effect of parathyroid hormone fragment 1-34. Moreover, at 10-100 microliters/ml it significantly decreased the histamine release by mast cells.

[Early myocardial involvement in collagen diseases. An endomyocardial biopsy study]

Endomyocardial biopsy was performed in three patients affected by systemic connectivitis (one case of systemic lupus erythematosus--SLE--, one of scleroderma and one of dermatomyositis). The analysis of the specimens revealed the presence of fibrosis and microvascular lesions (these latter only in SLE). Immunofluorescence showed in SLE and scleroderma perivascular IgG or perisarcolemmal IgM deposits respectively. Despite the scarcity of cardiac signs and symptoms, cardiac involvement can be early and frequent in connectivitis. The immune pathogenesis of the cardiac lesions seems to be possible because of the presence of immunocomplexes in the myocardium.

Parathyroid hormone fragment 1-34 inhibits drug-induced inflammation in various experimental models

We investigated the effect of the administration of rat parathyroid hormone-(1-34) on acute or chronic inflammatory processes in different experimental animal models. Fragment 1-34 of parathyroid hormone had an inhibitory effect in all inflammatory acute tests. The dose-response experiments showed that the maximal anti-inflammatory and anti-exudative effects appeared at the dose of 3.30 and 0.33 micrograms/kg, respectively. The anti-inflammatory effect was observed in the first phase of the inflammatory process. In the carrageenin-induced edema test the anti-inflammatory activity began to decline after 180 min. In contrast, this peptide was inactive in the inflammatory chronic test we used.

The effects of muscle-building exercise on forearm bone mineral content and osteoblast activity in drug-free and anabolic steroids self-administering young men

We measured bone mineral content (BMC) and bone density (BD) at appendicular sites by single photon absorptiometry in 18 men engaged in body-building exercises for at least 2 years, and in 14 age- and weight-matched controls. Eight exercises were using anabolic steroids by self-administration. Serum levels of bone Gla-protein (BGP), a reliable index of bone formation were also measured in all subjects. It was observed that muscle-building exercise was associated with increased BMC and BD at the distal radius, which contains both cortical and trabecular (more than 50%) bone. Previous authors have failed to detect any increase in BMC at mid radius, a site consisting almost entirely of cortical bone. Serum BGP levels were significantly higher in exercisers than in controls. If compared to drug-free exercisers, subjects taking steroids showed no significant increase of BMC, BD and serum levels of BGP. This study shows that muscle-building exercise is associated with increase in BMC and BD also at non-weight bearing sites, and that anabolic steroids did not provide, at the time of the observation, any further stimulus for osteoblast activity and bone formation.

Plasmatic markers of bone metabolism

Bone metabolism is characterized by continuous remodeling in which different cell lines, hormone systems and local mediators intervene. A useful method for the study of this process is evaluation of the physiopathological and clinical significance of substances which are involved in local turnover and at the same time are present in general circulation. These plasmatic markers are represented chiefly by bone-Gla-protein and alpha-HS-glycoprotein--peptides which belong to the more specific proteic component of the organic matrix in which reabsorption and neoformation take place, from the phosphatases to interleukin-1. Each one of these markers is described by analyzing the biochemical characteristics, the reciprocal correlations, and the potentials and limits in clinical practice. At present, none of these can guarantee formulation of a precise diagnosis of disease: they are, rather, biochemical indicators of the degree of bone turnover. The relevance of biochemical indicators becomes greater as the remodeling process increases, such as in Paget's disease. It lessens in conditions characterized by decreased cellularity such as osteoporosis. The study of these parameters during the course of therapeutic follow-up is extremely important.

Reduced axial bone mineral content in patients taking an oral anticoagulant

Recent literature indicates that the vitamin K cycle plays a role in the calcification process, presumably via its intervention on gamma-carboxylation of the noncollagenous proteins of bone osteocalcin and matrix gamma-carboxyglutamic acid protein. The major clinical evidence of this interference is fetal bone defect caused by oral anticoagulants given to the mother during the first trimester of pregnancy. No bone abnormalities have been reported so far in adults receiving oral anticoagulants. We studied 56 women who had had cardiac valve replacement and who were given acenocoumarol as anticoagulant, and 61 age-matched women who were in the same New York Heart Association functional class but who were not taking anticoagulants. Osteocalcin serum levels were comparable between the two groups; bone density values measured at appendicular bone were significantly lower in patients taking acenocoumarol. No significant correlation was found between duration of treatment and bone density. Significant osteopenia was present in the women being treated with oral anticoagulants.

Effect of parathyroid hormone, centrally or peripherally injected, on gastric activity in male rats

Parathyroid hormone (PTH) injected peripherally did not interfere with the development of experimental ulcers. Conversely, when PTH was administered i.c.v. the development of ulcers was significantly inhibited. The gastric secretory volume and acid output were also reduced. The possibility is discussed that this antisecretory activity of PTH may be due to a direct effect at the CNS level.

Endomyocardial biopsy in diagnosis and management of cardiovascular manifestations of systemic lupus erythematosus (SLE)

In recent years, the cardiovascular manifestations of systemic lupus erythematosus have became more apparent as a consequence of both prolonged survival and improvement in diagnostic modalities. We report the case of a 16-year old woman with systemic lupus erythematosus in whom the presence of cardiomyopathy was characterized by endomyocardial biopsy. This diagnostic technique also showed that the histologic hallmark of lupus myocardiopathy persisted despite corticosteroid and plasmapheresis, suggesting the need of a careful cardiac follow-up in these patients.

Effects of ovariectomy and 17 beta-estradiol on bone GLA protein in growing rats: an indirect evidence for estrogen receptors in bone cells

Estrogen deficiency after ovariectomy in the rat is followed by an increase of bone turnover and bone loss. Estrogens are thought to modulate the sensitivity of skeleton to Parathyroid Hormone; according to the recently reported evidence of estrogen receptors on osteoblasts, however, a direct effect on bone cells should not be ruled out. We studied the behaviour of Bone Gla Protein (Osteocalcin), a reliable marker of osteoblast function, in growing rats after ovariectomy and treatment with 17 beta-estradiol. Results indicate that ovariectomy stimulates, as expected, bone turnover, and that estrogen induces a further increase of osteoblast activity revealed by the rise of Bone Gla Protein plasma levels. This data may have clinical implications in humans, where estrogens are currently suggested for prevention and therapy of post menopausal osteoporosis.

Bone mineral content of the hyperprolactinemic rat femur by single photon absorptiometry

Chronic hyperprolactinemia was obtained in the rat by an implantation of two adenohypophyses under the kidney capsule. This experimental model was set to evaluate the influence that high prolactin levels may have on bone mineralization when an intervention of estrogens can reasonably be excluded. Bone density was measured by single photon absorptiometry at the femur level. Our results indicate that the increase in PRL throughout the period of observation was associated with a significant decrease in bone mineral content, while calcium and parathyroid hormone serum levels remained unchanged. This would suggest that PRL plays a role in bone calcium metabolism, that might be included among the effects of this hormone.

Postoophorectomy bone loss is associated with reduced bone Gla protein serum levels: a possible effect of osteoblastic insufficiency

To further investigate the relationship between oophorectomy (OF) and mineral bone loss, 15 women who underwent total hysterectomy and bilateral oophorectomy were studied for 12 months after surgery. Mineralometric and metabolic data were obtained before and after 3, 6, and 12 months. The women lost bone mineral content (measured by single photon absorptiometry) at the same rate they lost cortical and trabecular bone, suggesting that bone loss after OF is a generalized phenomenon. Our data also show that an increase in bone resorption takes place only in the first period after OF; the persistency of a negative bone balance up to 12 months, accompanied by a reduction of osteocalcin serum levels, may be dependent on a reduced bone formation, probably due to osteoblastic insufficiency.

Calcium-induced serum bone Gla protein variations in preterm newborns

The effect of calcium infusion on osteocalcin(Bone Gla Protein, BGP) serum levels were studied in a group of preterm newborns with bw appropriate for gestational age. Results showed that basal BGP serum levels in preterm newborns are higher than those reported at birth in normal infants. Moreover, calcium infusion induced a significant decrease in BGP values, inversely correlated with serum calcium. Since calcium loading increases both Ca availability for bone formation and BGP affinity for mineral surfaces, reduction of osteocalcin serum levels might reflect a shift of the protein from bloodstream to bone, suggesting an intervention in regulating an effective calcium uptake.

Effects of salmon calcitonin on plasma renin activity and systolic blood pressure in the rat

Salmon calcitonin, centrally injected, increased plasma renin activity and blood pressure in rats. It is possible that the peptide through an action on the central serotonergic tone stimulated plasma renin activity with subsequent enhancement of blood pressure. Conversely, peripheral administration of the peptide increased plasma renin activity but did not cause changes in blood pressure. Probably, the enhancement of renin may be a physiological response to the renal activity of calcitonin; however, this activity does not seem to involve urinary prostaglandins.

Effect of (Asu1,7)E-CT, synthetic analogue of eel-calcitonin, on nociceptive transmission

The effect of (Asu1,7)E-CT a deaminodicarba-analogue of the synthetic eel-calcitonin on the nociceptive transmission has been studied in mice. The analogue was intracerebroventricularly (0.0.5-0.01-0.02 U.I./kg) or intravenously (0.02-0.04-0.05 -0.1 U.I./kg) injected. This synthetic derivative of eel-calcitonin increased the antinociceptive effect also after peripheral administration. Moreover, preliminary studies on the time-course of this analogue showed that the dose of 0.1 U.I./kg i.v. injected, was able to elicit antinociceptive effect, already 5 min after the administration.

Long-term effects of histamine H2-receptor antagonists on serum parathyroid hormone in chronic renal failure

We assessed the effects of ranitidine and cimetidine (histamine H2-receptor antagonists) on the serum concentrations of parathyroid hormone (PTH) in 22 patients with end-stage chronic renal failure. Treatment for 3 months induced a significant decrease in serum concentrations of PTH determined by radioimmunoassay directed at the mid portion of the PTH molecule. In contrast, significant increases were noted using an assay directed at the amino-terminal portion, whereas no change was noted with a carboxy-terminal assay. No significant changes in serum calcium, phosphate and alkaline phosphatase were noted after treatment with either agent, but serum concentrations of osteocalcin increased significantly. We conclude the H2-receptor antagonists do not favourably influence the natural history of hyperparathyroid bone disease in patients with end-stage chronic renal failure.

Prolactin and calcium metabolism: influence of hyperprolactinemia on immunoreactive parathyroid hormone levels in man and in the rat

Serum prolactin, parathyroid hormone, P and Ca serum levels were measured in 15 patients (12 women and 3 men) with hyperprolactinemia, and in 6 normal male volunteers who underwent a TRH test (100 micrograms by rapid iv injection) in order to obtain a short-term pharmacologically-induced hyperprolactinemia. A pituitary gland graft under the kidney capsule was carried out on 26 Sprague-Dawley male rats, which became hyperprolactinemic since the transplanted pituitary was stripped of the inhibitory hypothalamic control. Another group of 10 rats was injected with L-sulpiride (0.1 mg/kg). The serum PTH levels in patients and in subjects with induced hyperprolactinemia were within the normal range and there was no correlation between serum PRL and PTH levels. The same occurred both in transplanted and L-sulpiride injected rats. Our results suggest that prolactin does not modify PTH secretion in vivo and therefore, in contrast with previous data, it should not be considered a physiologically relevant secretagogue for parathyroid hormone.

Hypoprolactinemic action of calcitonin and the tuberoinfundibular dopaminergic system

The effects of calcitonin on neurochemical parameters related to the tuberoinfundibular dopaminergic system have been investigated in an attempt to elucidate how calcitonin decreases serum prolactin levels. Intracerebroventricular human or salmon calcitonin injection decreases serum prolactin, medial basal hypothalamic dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) and hypophysial DA and increases hypophysial DOPAC. Results suggest that calcitonin may decrease prolactin secretion via the tuberoinfundibular dopaminergic system.

Daily modifications of plasma fibrinogen platelets aggregation, Howell's time, PTT, TT, and antithrombin II in normal subjects and in patients with vascular disease

The possibility of occurrence of daily variations in blood fibrinogen levels, platelets aggregation. Howell's time values and values for PTT, TT and antithrombin III was explored in 10 healthy subjects and in 10 patients with vascular disease. In normal subjects blood fibrinogen, platelets aggregation in ADP, PTT, Howell's time and TT values showed statistically significant daily variations, while the AT III values showed no significant variations over the 24-h cycle. In patients with vascular disease, on the other hand, the daily variations of the fibrinogen blood levels, of the maximum amplitude of platelets aggregation and of the Howell's values were not detected. In fact, the first two parameters remained consistently high and the third parameter remained consistently low throughout the 24-h cycle. In contrast, the PTT as well as the TT values in these patients showed statistically significant daily variations but with time patterns different than those found in normal subjects. Also, unlike to what obtained in healthy subjects, the AT III values in patients with vascular disease showed highly significant variations over the period of 24-h.

Circadian rhythm of plasma tryptophan in clinically healthy subjects and patients with endogenous depression

Variations of plasma tryptophan along the 24-h scale are studied in clinically healthy subjects and in patients with endogenous depression. In both groups a circadian rhythm in free and total tryptophan has been found. In healthy subjects plasma tryptophan levels were higher during the night in comparison with daytime hours; the opposite was demonstrated in depressed patients. The possible physiopathological mechanisms underlying the different behavior of plasma tryptophan in the 24-h span, in these two groups of subjects, are discussed.

Cimetidine-induced PTH variations in uraemic patients evaluated with the aid of antisera against the terminal carboxyl and amino groups of the hormone molecule

Eight uraemic patients on periodic haemodialysis were given 600 mg of cimetidine every day for 15 days. Parathyroid hormone levels before and at the end of this treatment were evaluated with two different antisera specific against the terminal -COOH and -NH2 groups of the hormone respectively. The results obtained suggest two things: though cimetidine may enhance PTH secretion, at the same time it accelerates peripheral disintegration of some of its metabolically active metabolites. It i therefore necessary to reconsider the possible use of cimetidine in the treatment of hyperparathyroidism associated with uraemia.

Effects of ketoprofen on the calciuric and uricosuric activities of calcitonin in man

The action of ketoprofen on the calciuric and uricosuric effects of porcine calcitonin in man is reported. The drug is capable of inhibiting both effects. This action is considered like an effect on CT receptors in the kidney or a competitive action on prostaglandin synthesis.