Biomedical subjects

L Moro

Publications and source records attributed to L Moro.

At least 19 recordsLinked to original sources

PubMed1998

Integrins induce activation of EGF receptor: role in MAP kinase induction and adhesion-dependent cell survival.

Adhesion of human primary skin fibroblasts and ECV304 endothelial cells to immobilized matrix proteins, beta1 or alphav integrin antibodies stimulates tyrosine phosphorylation of the epidermal growth factor (EGF) receptor. This tyrosine phosphorylation is transiently induced, reaching maximal levels 30 min after adhesion, and it occurs in the absence of receptor ligands. Similar results were observed with EGF receptor-transfected NIH-3T3 cells. Use of a kinase-negative EGF receptor mutant demonstrates that the integrin-stimulated tyrosine phosphorylation is due to activation of the receptor's intrinsic kinase activity. Integrin-mediated EGF receptor activation leads to Erk-1/MAP kinase induction, as shown by treatment with the specific inhibitor tyrphostin AG1478 and by expression of a dominant-negative EGF receptor mutant. EGF receptor and Erk-1/MAP kinase activation by integrins does not lead per se to cell proliferation, but is important for entry into S phase in response to EGF or serum. EGF receptor activation is also required for extracellular matrix-mediated cell survival. Adhesion-dependent MAP kinase activation and survival are regulated through EGF receptor activation in cells expressing this molecule above a threshold level (5x10(3) receptors per cell). These results demonstrate that integrin-dependent EGF receptor activation is a novel signaling mechanism involved in cell survival and proliferation in response to extracellular matrix.

3T3 Cells↗

PubMed1998

Release of matrix proteins from mitochondria to cytosol during the prereplicative phase of liver regeneration.

70% partial hepatectomy (PH) in the rat causes a release, into the cytosolic fraction, of mitochondrial matrix proteins, namely the mitochondrial isoform of aspartate aminotransferase (mAAT) and malate dehydrogenase (MDH), during the first 24 h after PH, when no growth of the residual liver is observed. After this time interval, the weight of the liver starts to increase and the normal weight is reached at 96 h after PH. This proliferative phase is characterized by a progressive recovery of the normal levels of intramitochondrial activities of mAAT and MDH. Mitochondria isolated at 24 h after PH show a membrane permeabilization to sucrose accompanied by a release of matrix enzymes; both are blocked by cyclosporin A. These results suggest an alteration of mitochondrial membrane integrity, during the prereplicative phase of liver regeneration, with the occurrence of an increased permeability that allows the passage into the cytosol of matrix enzymes.

Animals↗

PubMed1997

Chemical and structural characterization of the mineral phase from cortical and trabecular bone.

X-ray diffraction, infrared spectroscopy and chemical investigations have been carried out on the inorganic phases from rat cortical and trabecular bone. Although both inorganic phases consist of poorly crystalline B carbonated apatite, several significant differences have been observed. In particular, trabecular bone apatite displays reduced crystallite sizes, Ca/P molar ratio, and carbonate content, and exhibits a greater extent of thermal conversion into beta-tricalcium phosphate than cortical bone apatite. These differences can be related to the different extents of collagen posttranslational modifications exhibited by the two types of bone, in agreement with their different biological functions.

Animals↗

PubMed1997

Effects of 1- and 6-month spaceflight on bone mass and biochemistry in two humans.

The bone mineral density and the biochemical parameters exploring bone cell activities were analyzed in two cosmonauts who spent 1 and 6 months, respectively, in the Russian MIR station. Measurements were performed before the flight, after the flight, and after a recovery period. At the end of the first month, peripheral QCT measurements indicated a slight decrease of trabecular bone mass in the distal tibial metaphysis. However, after 6 months of spaceflight, a more marked loss of trabecular and cortical bones was observed in the tibia, and was still significant after 6 month recovery in the trabecular compartment, whereas a decrease was no longer observed in the cortical envelope. No change was observed in either compartment of the distal radius at any time. Ultrasound BUA of the calcaneus was greatly reduced by the first month, followed by a more dramatic decrease after month 6. Ultrasound SOS detected no change. Parameters reflecting bone formation activity appeared to be depressed after both missions. In contrast, no dramatic change in resorption parameters was observed, except for a trend toward an increase in pyridinoline. In conclusion, the lower weight-bearing bones appeared more sensitive than the upper ones in terms of spaceflight-induced bone loss. This probably explained the absence of marked systemic biochemical data changes. This study further suggests that recovery in the tibial trabecular compartment 6 months after landing was not completed after a 6 month mission.

Adult↗

PubMed1997

The irradiation of hepatocytes with He-Ne laser causes an increase of cytosolic free calcium concentration and an increase of cell membrane potential, correlated with it, both increases taking place in an oscillatory manner.

Isolated hepatocytes were irradiated with Helium-Neon laser (fluence: 0.24 Joules x cm-2, fluence rate: 12 mW x cm-2) and changes of both cytosolic free Ca2+ concentration and cell membrane potential were checked by measuring fura-2 and bis-oxonol fluorescence respectively. Irradiation resulted in an enhancement in cytosolic free Ca2+ concentration that requires the presence of Ca2+ in the phase outside hepatocytes; consistently an increase in cell membrane potential was measured correlated with it. Interestingly, the rate of increase of both cytosolic free Ca2+ concentration and cell membrane potential shows special time dependent features similar to those peculiar of oscillatory processes.

Animals↗

PubMed1997

17 beta-Estradiol and tamoxifen prevent the over-glycosylation of rat trabecular bone collagen induced by ovariectomy.

We have recently demonstrated that ovariectomy in the rat causes over-glycosylation of collagen which is restricted to trabecular bone. In order to obtain further evidence, we studied whether estrogen or tamoxifen treatment prevented over-glycosylation of trabecular bone collagen. Forty one-hundred-day-old female rats were subjected to ovariectomy (n = 30) or sham-operation (n = 10). Starting the day of the operation, sham-operated rats were treated with vehicle, while ovariectomized rats were divided into three groups and treated with vehicle (n = 10), estrogen (n = 10) or tamoxifen (n = 10). Five rats from each group were sacrificed at 115 and 145 days of age. Femurs and tibiae were separated into cortical and trabecular bone, demineralized, hydrolyzed and analyzed by HPLC for hydroxylysine glycoside and hydroxyproline content. Hydroxylysine glycoside content was expressed as a molar ratio with hydroxyproline. The results can be summarized as follows: 1) cortical bone collagen glycosylation did not vary among the different groups; 2) over-glycosylation of trabecular bone collagen observed in the ovariectomized rats was prevented by the administration of either 17 beta-estradiol or tamoxifen. These data demonstrated that estrogens affect glycosylation of trabecular bone collagen.

Animals↗

PubMed1997

Comparison of the clinical performance of the immunoenzymometric assays for N-terminal and C-terminal type I collagen telopeptides and the HPLC assay for pyridinium cross-links.

We evaluated the clinical performances of the immunoenzymometric assays for type I collagen N-terminal and C-terminal telopeptides and the HPLC assay for total deoxypyridinoline, in distinguishing between subjects with a moderately increased bone resorption rate (women in postmenopause) and subjects with normal bone resorption rate (women in premenopause). The postmenopausal group consisted of 61 women who had been in menopause for no more than 10 years, while the premenopausal group consisted of 52 healthy women with normal menstrual cycles. The biochemical markers were measured in a 24 hour urine sample and the results expressed as the molar ratio with urinary creatinine. The clinical performances were estimated by calculating the accuracy (as the area under a Receiver Operated Characteristic (ROC) curve: mean +/- SEM) and the discriminating power (as score) of each assay in distinguishing postmenopausal subjects from premenopausal subjects. Type I collagen C-terminal telopeptide, type I collagen N-terminal telopeptide and total deoxypyridinoline were significantly higher in the postmenopausal than in the premenopausal group (p < 0.01). Accuracies of these three markers ranged from 66.8 +/- 5.1% to 76.8 +/- 4.3%, while Z scores ranged from 3.54 to 5.67. Type I collagen C-terminal telopeptide, type I collagen N-terminal telopeptide and total deoxypyridinoline were not significantly different in their accuracy or discriminating power. All markers were highly correlated with coefficients of correlation ranging from 0.61 to 0.77. In summary, this study shows that 1) the immunoenzymometric assays for type I collagen N-terminal telopeptide and type I collagen C-terminal telopeptide show a high accuracy and discriminating power in distinguishing subjects with different bone resorption rate; 2) the results obtained with these immunoenzymometric assays are comparable to those obtained with the HPLC assay for total deoxypyridinoline. In conclusion our data support the use of the immunoenzymometric assays for type I collagen N-terminal telopeptide and type I collagen C-terminal telopeptide for estimating bone resorption.

Adult↗

PubMed1997

The influence of orchidectomy on collagen glycosylation of trabecular bone in rat.

This study evaluates the effect of male rat castration on the degree of collagen glycosylation of bone. Twenty 100-day-old male Sprague-Dawley rats were subjected to either orchidectomy (n = 10) or sham operation (n = 10). After surgery animals were divided at random into 2 groups: the first group (5 sham operated and 5 orchidectomized) was sacrificed under anesthetic at 130 days of age, while the second group (5 sham operated and 5 orchidectomized) was sacrificed at 250 days of age. Femurs and tibiae were separated into cortical and trabecular bone, demineralized, hydrolyzed and analyzed by HPLC for hydroxylysine glycosides and hydroxyproline content. Orchidectomy causes an increased collagen glycosylation only in trabecular bone, as already observed in ovariectomized rats. However, the effect was not seen in the group of 130 day old rats, i.e. 30 days after orchidectomy, but was evident in the 250 day old rats, i.e. at 150 days from castration. These data suggest that collagen glycosylation could also be controlled by testosterone.

Age Factors↗

PubMed1996

Collagen type I of rat cortical and trabecular bone differs in the extent of posttranslational modifications.

This study sought to evaluate whether the architecture of the matrix of cortical and trabecular bone is exactly the same. For this purpose we analyzed the extent of some posttranslational modifications of type I collagen, which is the major component of bone matrix. Ten female and 10 male 100-day-old rats were sacrificed and the content of hydroxylysine, glycosylated hydroxylysine, and pyridinium cross-links of collagen from cortical and trabecular bone was determined. The amount of each compound was expressed as a molar ratio with hydroxyproline. The collagen posttranslational modification pattern appears to be the same in both sexes but with a higher extent of differences in females compared with males. Comparing cortical and trabecular bone, the former contains a higher amount of hydroxylysine residues whereas in the latter, glycosylation of hydroxylysine is higher and pyridinium cross-link concentration is lower. Moreover, an inverse linear relationship between glycosylated hydroxylysine and pyridinium cross-links concentration was established, both for female (r = -0.455, P = 0.04) and male rats (r = -0.426; P = 0.06). This paper discusses what these findings may mean in functional terms.

Adrenal Cortex Hormones↗

PubMed1996

Clinical performances of galactosyl hydroxylysine, pyridinoline, and deoxypyridinoline in postmenopausal osteoporosis.

We have previously shown that galactosyl hydroxylysine (GHYL), pyridinoline (PYD), and deoxypyridinoline (DPD) have a better accuracy and discriminate power than hydroxyproline in distinguishing postmenopausal osteoporotic women from premenopausal controls. In this study, we evaluated the clinical performances of GHYL, PYD, and DPD, alone or in combination, in distinguishing postmenopausal osteoporotic women (OPBD, n = 26) from age-matched controls (CBD, n = 19). The diagnosis of osteoporosis was based upon the bone density (BD) of the lumbar spine measured by quantitative computed tomography (CBD: BD > 108 mg/cm3; OPBD: BD < 70 mg/cm3). Urinary excretion of GHYL, PYD, and DPD were measured by HPLC, and all data were expressed as the molar ratio with the creatinine excretion (GHYL/CR, PYD/CR, and DPD/CR). The clinical performances were tested by: Z score analysis (Z), Receiver Operated Characteristic curve analysis (%Acc) and logistic-regression analysis of the posterior probabilities for prediction from a logistic model (LOGIST). GHYL/CR, PYD/CR, and DPD/CR were significantly increased in OPBD compared with CBD. The clinical performances were similar for the three assays, with slightly better performances for GHYL/CR (GHYL/CR: Z = 3.14, %Acc = 70 +/- 8, LOGIST P = 0.01; PYD/CR: Z = 2.19, %Acc = 67 +/- 8, LOGIST P = 0.051; DPD/CR: Z = 2.13, %Acc = 65 +/- 8, LOGIST P = 0.06). None of the possible combinations of the three assays yielded better clinical performances than GHYL/CR alone. In conclusion, this study further confirms the validity of GHYL, PYD, and DPD as markers of bone resorption.

Aged↗

PubMed1995

Genomic organisation and chromosomal localisation of the gene encoding human beta adducin.

Adducin (ADD) is a heterodimeric protein of the membrane skeleton with subunits of 103 (alpha) and 97 kDa (beta). It promotes the assembly of the spectrin-actin network. We have previously shown that one point mutation in each of the alpha and beta rat ADD-encoding genes is associated with blood pressure variation in an animal model for hypertension, the Milan hypertensive strain of rats, probably due to a change in the phosphorylation pattern. In fact, the rat mutations, Y to F for alpha and R to Q for beta, are located, respectively, in a tyrosine kinase and a protein kinase A phosphorylation site. We have now determined, for the human beta-ADD-encoding gene, its chromosomal localisation, exon-intron organisation and alternative splicing patterns. We report here that human beta-ADD is localised on chromosome 2 and we also show a characteristic 3' end alternative splicing of the beta-ADD RNA that generates two distinct beta-ADD families, namely ADD 63 and 97; both of them in turn present a very complex differential splicing pattern in the internal exons.

Alternative Splicing↗

PubMed1995

Galactosyl hydroxylysine in assessment of Paget's bone disease.

Urinary galactosyl hydroxylysine/creatinine ratio (GHL) was used to assess rates of bone collagen degradation and the activity of the pagetic lesion as well as for monitoring the rate and degree of suppression of bone resorption over 1 year in patients treated with 30 mg of intravenous pamidronate for 3 consecutive days. The clinical utility of GHL was compared with that of urinary hydroxyproline/creatinine and deoxypyridinoline/creatinine and with bone isoenzyme of serum alkaline phosphatase. The results suggest that GHL is a quantitative marker of the activity of Paget's bone disease. GHL is less sensitive than hydroxyproline, deoxypyridinolone and bone alkaline phosphatase in monitoring treatment of Paget's disease. The assay of GHL is easier, faster and less costly than that of hydroxyproline or deoxypyridinoline and it can be easily standardized.

Adult↗

PubMed1995

Detection of pyridinium cross-links in human bile.

This study evaluated whether pyridinium cross-links, which are positively charged, besides renal clearance are also cleared by the liver into bile. In 13 human bile samples tested, we were able to detect both pyridinoline (PYD) and deoxypyridinoline (DPD) in small amounts which were estimated to be about 1-2% of the amount usually found in urine. To further evaluate the amount of pyridinium cross-links excreted through bile, we studied the stability of these compounds at the alkaline pH of bile. No effect on their stability was detected over a 6-hour incubation. The origin of these molecules in bile and the significance of this finding in the use of PYD and DPD as bone resorption markers are discussed.

Adult↗

PubMed1995

Angiokeratoma corporis diffusum and arteriovenous fistulas with dominant transmission in the absence of metabolic disorders.

BACKGROUND: A three-generation family with members affected by angiokeratoma corporis diffusum (ACD) and arteriovenous fistulas of the legs is described. Our purpose was to investigate possible lysosomal storage defects previously described in association with ACD. OBJECTIVE: Results of physical examination of both affected and unaffected family members were otherwise normal as was the life span. The inheritance pattern of both ACD and arteriovenous fistula traits was autosomal dominant, with variable expressivity and incomplete penetrance. Microscopic examination of ACD lesions showed dilated capillaries without vacuolation of cells. Ultrastructural studies failed to reveal lysosomal abnormalities. Normal levels of alpha-galactosidase, beta-galactosidase, alpha-fucosidase, and alpha-sialidase were detected in peripheral blood leukocytes and skin fibroblasts. CONCLUSIONS: The association of autosomal dominant ACD and arteriovenous fistulas might represent a novel syndrome. However, pathogenesis of these lesions remains unknown.

Adolescent↗

PubMed1995

Time-relationship between bone growth and increment of bone mineral content in growing rats.

The aim of the study was to describe the time-relationship between the growth rate of the rat tibia and the increase rate of its mineral content. Appositional and endochondral bone growth rates were derived from sequential X-rays measurements of tibial widening and lengthening, respectively; the increase rate of bone mineral content was derived from sequential photon absorptiometry measurements of the proximal tibio-fibular site. The time-relationship of appositional growth rate and endochondral growth rate versus bone mineral content increase rate was mathematically described. The results allow a better understanding of the time-course of two distinct features of bone growth: increase in size and increase in mineral content.

Absorptiometry, Photon↗

PubMed1994

Correction of the defective extracellular matrix of Ehlers-Danlos syndrome skin fibroblasts by dexamethasone.

Skin fibroblasts derived from Ehlers-Danlos syndrome (EDS) patients lack an organized extracellular matrix (ECM) of fibronectin (FN) and often show an accumulation of cytoplasmic FN. The treatment of EDS cells of different types (I to VIII) with 10(-7) M dexamethasone (dex), as well as cocultivation with control fibroblasts, induced in most cases the assembly of a FN-like ECM. The study of FN mRNA expression by dot-blot hybridization and of FN released into the culture media of EDS cells showed that the correction of the defective FN-ECM of EDS cells by dex treatment is associated in most cases with an increase of FN mRNA synthesis and of secreted FN.

Cells, Cultured↗

PubMed1994

The natural history of pre-type 1 (insulin-dependent) diabetes mellitus in patients with autoimmune endocrine diseases.

An 11-year prospective study was carried out in 180 non-diabetic patients with organ-specific autoimmune diseases to evaluate islet cell antibodies in predicting Type 1 (insulin-dependent) diabetes mellitus. Islet cell antibodies were characterised according to titres, persistence, complement-fixing ability, and pattern. During follow-up, 14 of 46 patients with islet cell antibodies persistently greater than 5 Juvenile Diabetes Foundation Units (JDF-U) (30.4%), none of 23 with islet cell antibodies between 2.5 and 5 JDF-U or fluctuating, and 3 of 109 without islet cell antibodies (2.7%), developed diabetes. The cumulative risk of developing diabetes was 70%, 0%, and 4%, respectively. All the patients who developed diabetes were females. Eight progressed to insulin-dependence acutely, four showed a transient period of non-insulin-dependence, while two were still insulin-free. No difference was found in titres of islet cell antibodies for the risk of diabetes. Complement-fixing islet cell antibodies enhanced the cumulative risk for the disease in patients with conventional islet cell antibodies at low-middle (> or = 2.5-40 JDF-U), but not at high (> or = 80 JDF-U) titres. Forty-two patients with islet cell antibodies were investigated for the whole or the selective pattern. In the presence of the whole pattern the cumulative risk for diabetes rose to 100%, while with the selective pattern it declined to 34%. The whole pattern was found in 83% of patients who developed Type 1 diabetes acutely. In patients with organ-specific autoimmune diseases, the whole islet cell antibody pattern greatly enhances the prediction for diabetes.

Adolescent↗

PubMed1994

Effect of bisphosphonate therapy and parathyroidectomy on the urinary excretion of galactosylhydroxylysine in primary hyperparathyroidism.

BACKGROUND: In patients with mild or asymptomatic primary hyperparathyroidism a reliable index of bone resorption might be useful for appropriate management. Hydroxyproline is the most commonly used marker of bone resorption but its low specificity and sensitivity are known. Galactosylhydroxylysine, an amino acid mainly represented in bone collagen, has been proposed as a more suitable index of bone resorption. In this study we evaluated the sensitivity of galactosylhydroxylysine and hydroxyproline assays in following the changes of their urinary levels in 12 patients with mild primary hyperparathyroidism before and after treatment with bisphosphonate and surgery. METHODS: Serum and fasting urine specimens were obtained from 12 women with mild primary hyperparathyroidism before and after bisphosphonate treatment (2.5 mg daily for 5 days, intravenously) and after a further 25 days; in 7 patients biochemical tests were also performed 1 and 6 days after parathyroidectomy. Galactosylhydroxylysine was assayed by an HPLC method and hydroxyproline by a RIA commercial kit. RESULTS: Baseline galactosylhydroxylysine urinary levels were far above the normal range in all the patients whilst in 8 of them baseline hydroxyproline levels were normal. Bisphosphonate treatment significantly decreased bone turnover as shown by a significant fall in serum calcium (from 2.9 to 2.6 mmol/l; P < 0.001) and in galactosylhydroxylysine and hydroxyproline (-55 and -31% respectively). Twenty-five days after the end of treatment, resorption increased again and serum calcium and galactosylhydroxylysine, but not hydroxyproline, rose significantly towards basal levels. One day after parathyroidectomy serum calcium, galactosylhydroxylysine and PTH showed reduction below normal ranges. PTH and galactosylhydroxylysine returned to normal values at day 6 after parathyroidectomy. No changes in hydroxyproline levels were seen. Galactosylhydroxylysine, but not hydroxyproline, correlated significantly with serum calcium and PTH. CONCLUSION: Galactosylhydroxylysine appears to be a sensitive index of bone resorption, useful in the clinical assessment of bone involvement and in the management of patients with mild primary hyperparathyroidism.

Aged↗