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Biomedical subjects

G Lupoli

Publications and source records attributed to G Lupoli.

At least 37 records · Page 2Linked to original sources

Modulation of molecular mechanisms involved in protein synthesis machinery as a new tool for the control of cell proliferation.

In the past years, the attention of scientists has focused mainly on the study of the genetic information and alterations that regulate eukaryotic cell proliferation and that lead to neoplastic transformation. All therapeutic strategies against cancer are, to date, directed at DNA either with cytotoxic drugs or gene therapy. Little or no interest has been aroused by protein synthesis mechanisms. However, an increasing body of data is emerging about the involvement of translational processes and factors in control of cell proliferation, indicating that protein synthesis can be an additional target for anticancer strategies. In this paper we review the novel insights on the biochemical and molecular events leading to protein biosynthesis and we describe their involvement in cell proliferation and tumorigenesis. A possible mechanistic explanation is given by the interactions that occur between protein synthesis machinery and the proliferative signal transduction pathways and that are therefore suitable targets for indirect modulation of protein synthesis. We briefly describe the molecular tools used to block protein synthesis and the attempts made at increasing their efficacy. Finally, we propose a new multimodal strategy against cancer based on the simultaneous intervention on protein synthesis and signal transduction.

Animals↗

Slow release lanreotide in combination with interferon-alpha2b in the treatment of symptomatic advanced medullary thyroid carcinoma.

Somatostatin analogs are promising agents in the treatment of medullary thyroid carcinoma. We have evaluated the effects of the slow release somatostatin analog lanreotide in combination with interferon-alpha2b in seven patients with advanced and symptomatic medullary thyroid carcinoma. The frequency and intensity of daily flushing episodes and bowel movements, the intensity of fatigue, weight, performance status, calcitonin levels, and change in tumor masses were recorded before and during treatment. No objective complete or partial responses were recorded. However, disease stabilization and minor tumor regression were observed in three of seven and two of seven patients, respectively. The number and intensity of bowel movements and flushing episodes decreased in five of six and two of two patients, respectively. Decrease in fatigue and improvement in performance status were observed in five of seven and six of seven patients, respectively. Weight gain was recorded in three of four patients. Plasma levels of calcitonin decreased significantly in six of seven patients. Clinical benefit, evaluated by a structured algorithm, was achieved in six of seven patients and was coupled with a decrease of 50% or more in serum calcitonin levels in three of seven patients. In conclusion, the combination of lanreotide with interferon had a major impact on clinical symptoms and was well tolerated.

Adult↗

Ret-mediated mitogenesis requires Src kinase activity.

The proto-oncogene RET encodes a transmembrane growth neurotrophic receptor with tyrosine kinase (TK) activity. RET mutations are associated with several human neoplastic and nonneoplastic diseases, including thyroid papillary carcinoma, multiple endocrine neoplasia type 2 syndromes, and Hirschsprung's disease. Activation of receptor TKs results in the binding and activation of downstream signaling proteins, among which are nonreceptor TKs of the Src family. To test the involvement of c-Src in Ret-mediated signaling, we measured the levels of c-Src activity in NIH3T3 cells coexpressing Ret and the accessory GFR alpha-1 receptor or an epidermal growth factor receptor/Ret chimeric receptor when the cells were stimulated by glial cell line-derived neurotrophic factor or epidermal growth factor, respectively. Ret stimulation resulted in the activation of c-Src. We also measured the levels of Src kinase activity in cell lines expressing isoforms of the Ret receptor activated by different mutations. These cells showed higher Src kinase activity than the normal counterpart. Furthermore, we show that Ret is able to associate with the SH2 domain of Src in a phosphotyrosine-dependent fashion. Microinjection of a kinase inactive mutant of c-Src blocked Ret-mediated mitogenic effect. These experiments demonstrate that activated Ret is able to bind and stimulate c-Src kinase and that Src activation is essential for the mitogenic activity of Ret.

3T3 Cells↗

Familial papillary thyroid microcarcinoma: a new clinical entity.

BACKGROUND: Familial, non-medullary thyroid carcinoma is clinically more aggressive than the sporadic form. We wanted to find out whether papillary thyroid microcarcinoma also occurs in a familial pattern, and, if so, to identify specific clinical and prognostic features. METHODS: We reviewed the clinical records of 119 patients with papillary thyroid microcarcinoma. Familial occurrence, together with clinical presentation, surgical treatment, pathological characteristics, and follow-up were recorded. FINDINGS: We identified a family history of thyroid carcinoma in seven patients. The tumour was multifocal in five patients, bilateral in three, and vascular invasion occurred in three of the seven patients. Lymph-node metastases were found in four patients. Three patients had a recurrence and one patient with pulmonary metastases died within 11 months. INTERPRETATION: We identified familial occurrence in 5.9% of cases of papillary thyroid microcarcinoma. The unfavourable behaviour in the familial form of papillary thyroid microcarcinoma suggests that radical treatment and careful follow-up are warranted.

Adult↗

Interferon-alpha induces apoptosis in human KB cells through a stress-dependent mitogen activated protein kinase pathway that is antagonized by epidermal growth factor.

We have demonstrated that interferon-alpha2-recombinant (IFNalpha) at growth inhibitory concentrations enhances the expression and signalling activity of the epidermal growth factor receptor (EGF-R) in human epidermoid carcinoma KB cells. Here we report that KB cells exposed to IFNalpha underwent apoptotic cell death and this effect was antagonized by EGF. We have also found that IFNalpha enhanced the expression of heat shock proteins (HSP) HSP-70, HSP-90 and HSP-27 and activated the NH2-terminal Jun kinase-1 (JNK-1) and p38 mitogen activated protein kinase, the target enzymes of a stress-dependent intracellular transduction pathway. Moreover, the overexpression of the wild-type JNK-1, obtained through plasmid transfection of KB cells, induced apoptosis which was potentiated by the exposure of wild-type JNK-1 (JNK-1wt)-transfected cells to IFNalpha. All these effects were neutralized by the addition of EGF to parental and JNK-1wt-transfected KB cells exposed to IFNalpha. In conclusion, EGF has a protective effect on KB cells from apoptosis while antagonizing a stress response elicited by IFNalpha and targeted on the stress pathway terminal kinases.

Apoptosis↗

[Urinary calcium excretion in a population of children living in Southern Italy].

BACKGROUND: Very few studies have evaluated the role of urinary calcium excretion as marker of bone metabolism in children. Normative data are lacking in these age groups. METHODS: In a group of 122 children (66 females e 56 males), mean age 108.13 +/- 18.73 months, attending a primary school in Nocera Superiore (Southern Italy) the following parameters were evaluated: sex, age, weight, height, BMI (weight/height2), urinary calcium excretion which was measured as the urinary calcium/creatinine concentration ratio (Uca/cr) in extemporaneous sample of the second urine in the morning. The Uca/cr ratio was not normally distributed in this childhood population. Natural logarithmic transformation was used to analyze the data. RESULTS: The mean value of Uca/cr was 0.125 +/- 0.102 mg/mg. A significant correlation was found between the Uca/cr ratio and sex. The Uca/cr ratio values were higher in girls than in boys. Mean Uca/cr was 0.144 +/- 0.113 mg/mg in females while it was 0.102 +/- 0.083 mg/mg in males ("t"-test: p < 0.05). No correlation was found between the Uca/cr ratio and other variables such as age, height, weight and BMI either in the simple or in the multiple linear regression analysis correcting both for the sex and the age. Data by age-group and sex were reported as percentile tables. CONCLUSIONS: The discussed variations of the Uca/cr in children from different areas and sex confirm the need for reference standards calculated in the different population groups.

Body Mass Index↗

Germline and somatic mutations of the RET proto-oncogene in apparently sporadic medullary thyroid carcinomas.

Medullary thyroid carcinomas (MTC) occur sporadically or as part of inherited multiple endocrine neoplasia (MEN) type 2 syndromes. To recognize misdiagnosed familial cases and to establish the frequency of somatic mutations, a series of 50 patients, clinically diagnosed with sporadic MTC, were analyzed for mutations in the RET proto-oncogene. The clinical management of the patient and of the family is different in the two cases. Germline mutations were detected in three independent cases, demonstrating that they were associated to familial MTC. The mutations affected exon 11 in two cases and exon 14 in one case. Somatic mutations were detected in eight patients (30%) and they were indicative of sporadic MTC. In seven cases the mutation affected codon 918 of exon 16 and in one case codon 634 in exon 11. No RET mutations were detected in the remaining patients. A different genetic and clinical management is proposed for individuals with a diagnosis of familial or sporadic MTC.

Carcinoma, Medullary↗

Molecular biology of the MEN2 gene.

Cancer is a genetic disease caused by 'gain of function' mutations of oncogenes and 'loss of function' mutations of tumour suppressors and of genes involved in DNA repair mechanisms. The RET gene encodes a tyrosine kinase receptor for molecules belonging to the glial cell line-derived neurotrophic factor (GDNF) family. RET is a paradigmatic example of how different mutations of a single gene can lead to different neoplastic phenotypes. Indeed, gene rearrangements, often caused by chromosomal inversions, activate the oncogenic potential of RET in a fraction of human thyroid papillary carcinomas. On the other hand, different point mutations activate RET in familial multiple endocrine neoplasia syndromes familial medullary thyroid carcinoma (FMTC), MEN-2A and MEN-2B. Little information is so far available on the biochemical mechanisms by which the potent transforming and mitogenic signals of RET are delivered to the nucleus. However, recent data indicate coupling to the Shc-Ras-MAPK pathway as a necessary step in RET signal transduction.

Carcinoma, Papillary↗

Glial cell line-derived neurotrophic factor differentially stimulates ret mutants associated with the multiple endocrine neoplasia type 2 syndromes and Hirschsprung's disease.

Ret is a receptor tyrosine kinase involved in several neoplastic and developmental diseases affecting the thyroid gland and tissues of neuroectodermal origin. Different ret mutations are associated with different disease phenotypes. Gain-of-function of ret is caused by gene rearrangements in thyroid papillary carcinomas and by point mutations in multiple endocrine neoplasia (MEN) type 2A syndrome (MEN2A), in familial medullary thyroid carcinoma (FMTC), and in the more severe MEN2B syndrome. Conversely, Hirschsprung's disease (HSCR) is associated with loss of function of ret. Recently, it has been shown that glial cell line-derived neurotrophic factor (GDNF), by binding to the accessory molecule GDNFR-alpha, acts as a functional ligand of Ret and stimulates its tyrosine kinase and biological activity. To ascertain whether the biological effects of ret mutations are modulated by GDNF, we have investigated the responsiveness to GDNF of ret mutants in cell lines coexpressing GDNFR-alpha and MEN2A-, MEN2B-, FMTC-, or HSCR-associated ret mutants. Here, we show that triggering of GDNF affected only ret/MEN2B, i.e. it stimulated ret/MEN2B mitogenic and kinase activities, as well as its ability to phosphorylate Shc, a bona fide Ret substrate. In contrast, ret mutants associated with MEN2A or FMTC (carrying Cys634 or Cys620 mutations) were unresponsive to GDNF. HSCR mutations, by affecting either the extracellular or the intracellular Ret domain, impaired responsiveness to GDNF. These data suggest that the phenotype of human diseases caused by ret mutations can be differentially influenced by GDNF.

3T3 Cells↗

Bone mineral density in premenopausal women receiving levothyroxine suppressive therapy.

Osteoporosis is a well-known complication of thyrotoxicosis. Prolonged subclinical hyperthyroidism due to L-thyroxine treatment has been associated with reduced bone mass and thus with the potential risk of premature development of osteoporosis. The aim of this study was to assess the effect of a chronic L-thyroxine suppressive treatment on bone mineral density (BMD) in a group of premenopausal women. Forty consecutive patients (mean age +/- SE = 40.95 +/- 1.56 years) affected by non-toxic goiter underwent bone mineral densitometry (dual energy X-ray absorptiometry; DEXA) of the lumbar spine (L1-L4) and right femoral neck. At the time of the study the patients had been under thyroid stimulating hormone (TSH) suppressive therapy for 74.95 +/- 10.34 months (range 17-168 months). Baseline levels of free thyroxine (fT4), free triiodothyronine (fT3), TSH, calcium and phosphorus were measured and correlated with BMD. The age of starting, duration of treatment, main daily dose, cumulative dose of treatment and body mass index (BMI) were also correlated with BMD. Statistical analysis was performed by multiple linear regression. BMD among female patients was not significantly different from that of the general population matched for age and sex. With the use of the regression model, no significant correlation was found between BMD and the variables considered. In conclusion, our data suggest that L-thyroxine suppressive therapy, if carefully carried out and monitored, has no significant effect on bone mass.

Adult↗

[New developments in the treatment of medullary thyroid carcinoma].

Medullary thyroid carcinoma arises from the C cells, which produce a characteristic hormone, calcitonin. At present, surgery is the main treatment modality. Medullary thyroid carcinoma is usually treated with total thyroidectomy and with removal of nodes in the central portion of the neck and upper mediastinum. Cervical nodes dissection may be required for cancers affecting lateral neck nodes. Substitutive therapy with levo-thyroxine is indicated after surgery. External beam radiation therapy is not effective against advanced medullary thyroid carcinoma, while chemotherapy has a marginal activity. Biological therapy induces its anti-tumour activity through the inhibition of tumour cell growth without cytolysis and stimulating the antitumour immune response, in the absence of relevant side effects. On these bases, it can be suggested that chemo-refractory tumours could be still responsive to biological agents. In the last years somatostatin analogues and interferon have been used in the therapy of advanced and symptomatic medullary thyroid carcinoma, demonstrating an efficacious effect on neuroendocrine symptoms and on the production of calcitonin and an improving in quality of life. Even if there are no consistent data on the effects of biological agents on the reduction of tumour mass, the combined use of chemotherapy and biological therapy needs to be experimented in medullary thyroid carcinoma.

Carcinoma, Medullary↗

Short stature and azoospermia in a patient with Y chromosome long arm deletion.

We report on a 42-year old male with short stature, azoospermia and a wide deletion of long arm of Y chromosome. On physical examination, the patient showed height of 149 cm (< 1 degree centile) and reduced volume (3 ml) and consistency of the testes. On hormonal evaluation, he showed increased serum gonadotropins and normal serum testosterone levels though its HCG stimulated levels were limited. Serum thyroid hormones were normal. Serum GH levels in baseline evaluation as well as after GHRH and GHRH + pyridostigmine administration were normal. Serum IGF I levels were lower than normal in baseline evaluation whereas its response to the GH administration was in the normal range. The bilateral testicular biopsy showed tubular atrophy, hyalinosis, interstitial sclerosis and a histological picture of a Sertoli cell only syndrome. Moreover the patient showed arthropathy, otopathy, small chin, small mouth and truncal obesity. On genetic evaluation, the patient showed a 46,X,delY (pter--q11.1:) karyotype and loss of several DNA loci on Yq. In fact he preserved short arm SRY, centromeric DYZ3 and more proximal euchromatic region Yq loci, including DYS270, DYS271, DYS272, DYS11, DYS273, DYS274, DYS148, DYS275, and missed more distal DNA loci from DYS246 to DYZ2. These results disclosed a wide Y long arm deletion, including all hypothized Yq azoospermia loci (except for AZFa and probably for one of the RBM genes, which lie proximally to the deletion) and possibly the Y-specific growth control region (GCY), mapped between DYS11 and DYS246 loci. This deletion is responsible for the complete azoospermia of the patient and probably also for his short stature, even if other factors could be implicated in the statural impairment. It further possibly allowed to relate the GCY gene(s) to the control of GH or IGF-I receptor or post-receptor pathway, being the alteration of this gene(s) consistent with the hormonal pattern of the patient.

Adult↗

Gonadotropin-releasing hormone agonists administration in polycystic ovary syndrome. Effects on bone mass.

Women with amenorrhea and polycystic ovaries (PCO) seem to present a relative degree of protection against bone loss caused by hypoestrogenism. We treated 20 patients affected by polycystic ovary syndrome (PCOS) with a gonadotropin-releasing hormone agonist (GnRH-a) for 6 months. After treatment mean bone mineral density (BMD) significantly decreased. We concluded that patients with PCOS have to be considered at risk of developing osteopenia when treated with GnRH-a. The relative protection against osteoporosis, that is present in amenorrheic patients with PCO, might be attributed to the characteristics of amenorrhea in these patients.

Acne Vulgaris↗

Treatment of advanced medullary thyroid carcinoma with a combination of recombinant interferon alpha-2b and octreotide.

BACKGROUND: The medical treatment of advanced medullary thyroid carcinoma (MTC) is still questionable. Results of chemotherapy are disappointing with almost no curative responses, few partial responses, and many side-effects. A recent report has suggested the activity of combination recombinant interferon alpha-2b (rIFN-alpha-2b) and octreotide, a somatostatin analogue, in the treatment of a metastatic carcinoid tumor. This new therapeutic schedule may be used in other neuroendocrine tumors. In this study we evaluated the therapeutic effectiveness of octreotide and rIFN-alpha-2b in patients with advanced MTC. METHODS: Eight patients affected by advanced MTC received octreotide at a daily dose of 150 micrograms for 6 months and subsequently at a daily dose of 300 micrograms for another 6 months, subcutaneously, and rIFN-alpha-2b at a daily dose of 5.000.000 IU intramuscularly 3 times a week for 12 months. Plasma calcitonin, carcinoembryonic antigenic levels, and morphologic staging were evaluated at 0, 1, 3, 6, and 12 months. RESULTS: The therapy was stopped in two patients because of diarrhea and toxicity of drugs used. Pre-existing diarrhea in four patients and flushing in one significantly improved during treatment. A maximum decrease of calcitonin was reached after 1 month in 2 patients and after 3 months in 4. In all of the patients carcinoembryonic antigen levels decreased during treatment. No significant changes of size of metastases were observed. CONCLUSIONS: The combination of octreotide and interferon is well tolerated and can be recommended for the treatment of advanced MTC.

Adult↗

Effects of alendronate on bone loss in pre- and postmenopausal hyperthyroid women treated with methimazole.

High levels of thyroid hormones accelerate bone turnover. The aim of the present study was to evaluate the effects of treatment with alendronate in patients affected by hyperthyroidism and osteoporosis. We studied 40 hyperthyroid patients with bone loss, divided into two groups according to menopausal state. Before treatment and after 6 and 12 months, serum thyroid hormones levels, serum osteocalcin level and bone mineral density were evaluated. In all patients we observed an increase in bone mineral density after treatment with alendronate, and a corresponding decrease in serum osteocalcin level.

Adult↗

[Risk factors and prevention of thyroid carcinoma].

Thyroid carcinoma represents the most frequent endocrine tumor. Recent reports have documented an increase in the incidence of thyroid cancer. Its incidence varies geographically around the world from 0.9/ 100,000 men and 2.4/100,000 women in Great Britain to 8.8/100,000 men and 18.2/ 100,000 women in Hawaii. Radiation exposure has been strongly implicated as an aetiological factor. The greatest risk occurs with acute exposure to X and/or gamma rays, with a linear dose response curve, while the risk is inversely related to age at exposure with a latent period of 5-20 years. Together with irradiation, other factors (iodine, alcohol and calcium diet intake, hyperthyroidism, Hashi-moto's thyroiditis, Gardner syndrome, Cowden syndrome, pharmaceutical agents, hormonal factors, occupational exposure, activation of cellular oncogenes) have been associated with the risk of thyroid cancer. In prevention a policy should include regulations and methods for avoiding radiation exposure of the thyroid and for preventing nutritional deficiency and excess of iodine. Besides, early and continuous suppressive therapy of all patients affected by non-toxic goiter or treated previously with thyroidectomy, and a screening of medullary thyroid carcinoma (MTC) using pentagastrin stimulation test and restriction fragment length polymorphism analysis, in subjects with a familial history of MTC, are of paramount importance to prevent thyroid cancer.

Adenocarcinoma, Follicular↗

Surgical management and follow-up of medullary thyroid carcinoma.

Between 1977 and 1990 we operated on 33 patients with medullary thyroid carcinoma. We performed total thyroidectomy in 31 patients and central node dissection and/or lateral modified node dissection in 21 patients (63.3%). Two patients underwent radiotherapy after subtotal resection and tracheostomy. No perioperative death occurred. Twenty-five patients were followed (mean follow-up, 63.8 months) and 8 others were unavailable for follow-up. Three patients (1 with multiple endocrine neoplasia type IIB, 2 sporadic with distant metastases) died of their disease at 12, 18 and 36 months after initial operation. Of the remaining 22 patients, 4 with stage II disease were normocalcitoninemic even with pentagastrin stimulation, following total thyroidectomy and bilateral modified neck dissection and central node dissection. Eighteen other patients continued to have elevated calcitonin levels postoperatively. Only 10 patients with known cervical metastatic disease were reoperated upon. We performed extensive node dissection in all. In addition we resected recurrent tumor from the thyroid bed in 4 patients. Despite these extensive reoperations no patient became normocalcitoninemic. At the completion of the study (December 1991), 22 of the 25 patients followed were alive: 4 patients with normal calcitonin levels, baseline and after pentagastrin stimulation, and 18 with persistent mildly elevated calcitonin levels but no other evidence of disease. Our experience supports a very aggressive surgical approach at the time of the first operation for patients with medullary thyroid carcinoma. A lesser operation usually resulted in residual medullary thyroid carcinoma in the neck. We demonstrate the difficulty of achieving a cure by reoperation once the tumor becomes demonstrable by localization studies.

Adolescent↗