Giant single coronary artery with terminal fistulous aneurysm: a rare entity.
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Adult↗
Biomedical subjects
M Adamo
Publications and source records attributed to M Adamo.
Severe obstructive jaundice in a 90-year-old man caused by an annular pancreas. Report of a case.
Although the annular pancreas is a rare congenital malformation of the pancreatic glandular parenchyma, this pathology often remains asymptomatic until the adult or old age and can represent an incidental finding during an ERCP or an abdominal Computed Tomography, because the clinical appearance of this condition can be of very various kinds. We present a case of an extra-hepatic jaundice in a 90-year-old man, caused by an annular pancreas constricting coledochus. Description of this case results very interesting and particular for two reasons: the very old age of the patient, probably the oldest recorded, and the unusual clinical appearance: obstructive jaundice as beginning one symptom of this malformation.
Aged↗
FILO (field interaction ligand optimization): a simplex strategy for searching the optimal ligand interaction field in drug design.
A method (FILO, Field Interaction Ligand Optimization) for obtaining the optimal molecular interaction field was developed on the basis of the Simplex optimization procedure applied to a matrix of interaction energies obtained by performing a GRID computation on a suitable data set. The FILO procedure was tested on a set of nine HIV-1 protease inhibitors with known crystal structures. The results of FILO consist of the optimal molecular interaction field of a putative new ligand with optimal binding affinity. The final FILO model yields R2 and R2(CV) values of 0.993 and 0.936, respectively, and finds eight negative and four positive interaction nodes for the OH probe taken as an example. The eight H bonding interactions pointed out by FILO identified well the binding site AA-residues Gly A27, Asp A29, water 501, Gly B48 and Asp A25 of HIV-1 protease.
Drug Design↗
Role of nuclear medicine in the treatment of malignant gliomas: the locoregional radioimmunotherapy approach.
The high-grade malignant gliomas (anaplastic astrocytomas and glioblastoma) have a very bad prognosis since the available methods of treatment (surgery, radiotherapy and chemotherapy) are unable to control the progression of the disease for long. The use of specific monoclonal antibodies labelled with a suitable isotope (iodine-131 or yttrium-90) represents an effective approach to hamper tumour regrowth. Some authors have injected the antibodies intravenously, or have tried to increase the tumour/background ratio with the avidin/biotin system. In many cases the labelled monoclonal antibodies were injected directly into the tumoral bed after the operation. The authors' experiences concern a quite large locoregional radioimmunotherapy study which was performed by using antitenascin antibodies labelled initially with 131I and more recently with 90Y. The clinical results demonstrate the ability of this technique to control, for a long time, the growth of these tumours. The glioblastoma median survival was prolonged to 25 months (131I group) or 31 months (90Y group). The response rate (which comprises PR, CR and NED) was 47.1% (glioblastoma 131I group) or 40% ( glioblastoma 90Y group). In many cases a significant tumour shrinking effect was radiologically demonstrated. The use of 90Y proved more favourable in bulky lesions, and reduced the radioprotection problems.
Antibodies, Monoclonal↗
[Comparison of the echo-dobutamine-atropine test and ergometric test in the diagnosis of coronary disease].
BACKGROUND: A prospective study has been done on 46 patients with suspected coronary artery disease (CAD). They had no history of myocardial infarction (MI) and a normal basal kinetic echocardiography. This was done in order to evaluate the overall accuracy of dobutamine-atropine stress echocardiography (DAS) compare to exercise stress test (ET) for the diagnosis of CAD. METHODS: All the patients after suspension of coronary therapy, performed a casual sequence with both maximal or symptom limited exercise testing (treadmill-Bruce protocol) and DAS. The dobutamine has been given while monitoring systemic blood pressure, electrocardiography and echocardiography in steps of 10 mcg/kg/min' per 3 min' up to a maximum of 40 mcg/kg/min'. Atropine has been added (0.25-1 mg) in patients who did not reach the theoretical maximal cardiac frequency. The test is considered positive when kinetic segmental left ventricular dysfunction appeared. CAD was defined as 50% luminal area stenosis in at least 1 coronary artery at coronary angiography. RESULTS: Significant CAD was present in 27/46 patients (59%). Compared with ET, DAS had significantly higher sensitivity (59% vs 92%, p = 0.01). The different sensibility between the two tests was higher on these patients with a 1 vessel disease (40% vs 86%, p = 0.02). There were no significant differences in specificity among the two tests (79% vs 84%, respectively). Differences in overall accuracy between ET and DAS were significant (67% vs 89%, p = 0.02). CONCLUSIONS: The results of our study show that the DAS is a safe and feasible technique with high sensibility (especially in patients with single CAD) and specificity. This is a valid alternative to the traditional ET, especially for these patients unable to exercise or these who are poorly motivated to achieve a work load sufficient to make the test interpretable.
Adult↗
Molecular and cellular aspects of insulin-like growth factor action.
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Animals↗
Insulin-like growth factor receptors. Implications for nervous system function.
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Animals↗
Failure of senescent human fibroblasts to express the insulin-like growth factor-1 gene.
Senescent human diploid fibroblasts express several growth-regulated genes but fail to express others. In this paper we show, by a very sensitive technique (reverse transcriptase-polymerase chain reaction), that senescent cells fail to express insulin-like growth factor-1 (IGF-1) mRNA, which is expressed in moderate amounts by young cells. Human fibroblasts immortalized by transfection with a temperature-sensitive SV40 T antigen gene regain the ability to express IGF-1 mRNA, but only at the permissive temperature of 34 degrees C. Under these conditions, the immortalized human fibroblasts grow even in 1% serum. At the restrictive temperature of 39 degrees C, the temperature-sensitive T antigen is nonfunctional, IGF-1 RNA is not detectable, and the cells fail to grow even in 10% serum. The failure to express IGF-1 mRNA in postsenescent cells can be ascribed, at least in part, to a transcriptional mechanism. Despite the correlation among immortalization by SV40 T antigen, expression of IGF-1, and growth, it seems unlikely that the failure to express IGF-1 is the sole cause of cellular senescence; other requirements must be postulated.
Antigens, Polyomavirus Transforming↗
The growth-stimulatory effect of simian virus 40 T antigen requires the interaction of insulinlike growth factor 1 with its receptor.
We have used a plasmid expressing a temperature-sensitive (ts) mutant of simian virus 40 (SV40) T antigen, stably transfected into 3T3 cells, to study the role of insulinlike growth factor 1 (IGF-1) and its receptor in T-antigen-mediated growth. While 3T3 cells do not grow in serum-free medium, in 1% serum, or with the sole addition of either platelet-derived growth factor (PDGF) or IGF-1, cells expressing the tsA T antigen (BALB 58 cells) grow at 34 degrees C in either PDGF or 1% serum but not in IGF-1. At the restrictive temperature (39.6 degrees C), these cells can only grow in 10% serum. We show that BALB 58 cells, at 34 degrees C, have a markedly increased expression of IGF-1 and IGF-1 mRNA and that their growth in 1% serum (at 34 degrees C) is inhibited by an antisense oligodeoxynucleotide to the IGF-1 receptor RNA. When this tsA plasmid is stably transfected into cells constitutively overexpressing the human IGF-1 receptor cDNA, the resulting cell lines show a constitutively phosphorylated IGF-1 receptor and grow in serum-free medium at 34 degrees C (but not at 39.6 degrees C). A functional SV40 T antigen also increases the expression of a plasmid in which the reporter luciferase gene is under the control of a rat IGF-1 promoter. We conclude (i) that the SV40 T antigen induces the expression of IGF-1 and IGF-1 mRNA, at least in part by a transcriptional mechanism, thus altering the growth factors requirements, and (ii) that, in BALB/c3t3 cells, the SV40 T antigen necessitates a functional IGF-1 receptor for its growth-stimulating effect in low serum (or PDGF).
3T3 Cells↗
How distinct are the insulin and insulin-like growth factor I signalling systems?
Insulin and insulin-like growth factor I (IGF-I) are closely related peptides. Insulin is primarily involved in regulating carbohydrate, fat and protein metabolism. IGF-I, however, regulates growth and development of the whole organism as well as differentiated functions in specific tissues. Each of these functions are mediated by specific tyrosine kinase receptors expressed on the cell surface. The insulin and IGF-I receptors, though separate gene products, are very similar. Amino acid similarities range between 40 and 85% in different domains, the highest degree of homology being found in the tyrosine kinase domain. Tertiary structure similarities further explain the interactions of each ligand with the heterologous receptor; thus insulin receptors bind insulin with high affinity and IGF-I with lower affinity, and the opposite is true for the IGF-I receptor. Since each ligand can stimulate both receptors and both receptors seem capable of mediating both metabolic and growth activities, what separates these two distinct physiological roles? The interaction of the ligands with their own specific high affinity receptors is facilitated by the presence of IGF-specific binding proteins (BPs) which, however, do not bind insulin. These BPs, found both in the circulation and in tissues, bind all the circulating IGFs and transport the IGFs to their target tissues, thus ensuring that at physiological concentrations IGF-I will only interact with its own receptor. Furthermore, they modulate IGF effects. Since insulin circulates at much lower concentrations compared with the IGFs, this ensures that insulin will only interact with high-affinity insulin receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
The inhibition of insulin action and glucose metabolism by porcine growth hormone in porcine adipocytes is not the result of any decrease in insulin binding or insulin receptor kinase activity.
The present study was undertaken to determine the effects of porcine growth hormone (pGH) on glucose transport, to establish which lipogenic enzymes were affected by pGH, and to determine if changes in insulin binding or insulin receptor kinase activity contributed to the diminished insulin responsiveness of adipocytes from pigs treated with pGH. Pigs were treated with pGH daily (70 micrograms/kg body wt.) for 7 days. pGH treatment reduced the basal (non-insulin-stimulated) glucose transport rate by 62% and the insulin-stimulated transport rate by 47%. The decline in glucose transport rate was paralleled by a 64% decrease in fatty acid synthesis. The reduction in the lipogenic rate was associated with a marked decline in the activity of several lipogenic enzymes: glucose-6-phosphate dehydrogenase (50% decrease), 6-phosphogluconate dehydrogenase (11% decrease), malic enzyme (62% decrease) and fatty acid synthase (activity not detectable after pGH treatment). The pGH-dependent decline in insulin responsiveness was not associated with any change in the binding of insulin to intact adipocytes or to plasma membrane preparations. The insulin-stimulated tyrosine kinase activity of the wheat-germ agglutinin-purified receptors from pGH-treated adipocytes was not different from that in control adipocytes, except when high concentrations of insulin were employed. These findings establish that pGH elicits a number of metabolic effects in porcine adipocytes which collectively diminish the rate of lipid synthesis, and thereby contribute to the decrease in lipid deposition observed in pGH-treated pigs. Furthermore, the pGH-dependent impairment in insulin action appears to be mediated at some location distal to the receptor kinase step or in other signal pathway(s) which mediate the biological effects of insulin that are not dependent on activation of insulin receptor tyrosine kinase activity.
Adipose Tissue↗
[Etozolin and captopril in the treatment of arterial hypertension].
Etozolin is a new diuretic with hypotensive properties. The above research was aimed to evaluating the effects of etozolin, captopril and their combination in a group of 30 patients with essential hypertension; age range 42-74 years, average 76.6. Patients were subdivided into two groups for a controlled cross-over trial. Group I was treated for 4 weeks with daily etozolin doses of 200 mg, and, after a period of withdrawal until basal values were restored, for a further 4-week period with captopril, 25 mg 3 times daily. Group II had the same treatments in the opposite order. After this cross-over experiment, all patients were treated for 16 weeks with both drugs in combination at the same dosage. Treatment with etozolin led to a reduction of arterial blood pressure from 187/112 +/- 10/4 mmHg to 167/99 +/- 7/6 mmHg; for captopril the corresponding figures were from 186/112 +/- 11.5 mmHg to 163/98 +/- 7.4 mmHg and for the combination from 188/112 +/- 10/5 mmHg to 154/86 +/- 6/5 mmHg. These findings confirmed the efficacy of etozolin and captopril alone; the combination of the two drugs led to a significantly more marked reduction of pressure values compared to monotherapy and neutralized such biochemical changes as had been observed after administration of the two drugs alone. Tolerance was excellent for all treatment schedules used.
Adult↗
Pulsatile growth hormone secretory pattern: autofeedback regulation and effects on growth factors.
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Animals↗
Expression and stability of insulin-like growth factor-I (IGF-I) mRNA splicing variants in the GH3 rat pituitary cell line.
We have employed Northern blot analyses and solution hybridization/RNase protection assays to evaluate the presence and stability of IGF-I mRNA splicing variants in the GH3 rat pituitary cell line. All of the IGF-I mRNA size classes and IGF-I mRNAs with alternately-spliced 5'-untranslated regions and E-peptide coding regions seen in adult rat liver also were present in GH3 cells, although the proportions of the 5' splicing variants were significantly altered. In actinomycin D-treated cells, all IGF-I mRNA splicing variants were equally stable; thus, changes in the levels of some splicing variants were not due to differential mRNA stability. Additionally, all IGF-I mRNA size classes seen on Northern blots were equally stable; this data suggests that the large IGF-I mRNA species is not a precursor of the smaller species.
Actins↗
Insulin and IGF-I stimulate phosphorylation of their respective receptors in intact neuronal and glial cells in primary culture.
Previous studies have shown that insulin and IGF-I bind to their respective receptors and stimulate autophosphorylation of the receptor beta subunits in detergent extracts of neuronal and glial cells. In the present study, intact neuronal and glial cells in primary culture have been utilized to characterize insulin- and IGF-I-stimulated phosphorylation of their receptors. Following [32P]orthophosphate labelling and stimulation by insulin or IGF-I, the cells were solubilized and the phosphorylated receptors were partially purified on wheat germ agglutinin--agarose columns, and immunoprecipitated using anti-phosphotyrosine or anti-insulin receptor antibodies. Insulin stimulated the phosphorylation of its receptor beta subunit (95 kD phosphoprotein) in a dose-dependent manner, within at least 20 seconds in both neuronal and glial cells. Additionally, a 102-kD phosphoprotein was observed in insulin-stimulated neuronal cells. Maximal stimulation of receptor phosphorylation occurred at 1 minute for the glial cells, and 10 minutes for the neuronal cells. IGF-I stimulated the phosphorylation of two phosphoproteins in intact neuronal and glial cells; a 95-kD protein and a 102-kD protein, in a dose-dependent manner. These observations demonstrate that both insulin and IGF-I stimulate the phosphorylation of the beta subunits of their respective receptors in brain cells in a similar fashion to their effects on receptors from nonneural tissues.
Animals↗
Developmental regulation of the rat insulin-like growth factor I receptor gene.
We have investigated the developmental regulation of the rat insulin-like growth factor I (IGF-I) receptor gene in various tissues using a sensitive and specific solution hybridization/RNase protection assay. For this purpose we characterized rat IGF-I receptor cDNAs that were cloned from a simian virus 40-transformed rat granulosa cell cDNA library. The specific cDNA clone used in these studies encoded the putative signal peptide and the first 53 amino acids of the alpha subunit and was approximately 94% homologous to its human counterpart. IGF-I receptor gene expression was studied during the perinatal period and at various intervals until early adulthood. Overall, steady-state IGF-I receptor mRNA levels decreased dramatically during postnatal development; however, the extent of the decrease differed among the various tissues studied. In contrast to receptor mRNA levels, IGF-I mRNA levels increased in some of the same tissues. The molecular mechanisms underlying this apparent divergent transcriptional control of the IGF-I and IGF-I receptor genes warrant further study.
Amino Acid Sequence↗
Liver insulin receptor tyrosine kinase activity in a rat model of type II diabetes mellitus and obesity.
Spontaneous hypertensive-corpulent rats (SHR/N-corpulent), homozygous for the corpulent gene (cp/cp), are obese, hyperinsulinemic and exhibit abnormal glucose tolerance and thus represent a model for type II diabetes and obesity. In view of their overall insulin resistance, we examined liver insulin receptor binding and tyrosine kinase activity from corpulent rats and lean littermates fed purified diets containing 54% sucrose or starch for about 12 wk. Specific 125I-insulin binding to crude liver membranes from female corpulent rats fed either starch or sucrose was reduced to approximately 50% of that seen in lean rats (14 vs. 7%). Affinity of insulin receptors was similar in all groups, suggesting that hyperinsulinemic corpulent rats possess fewer hepatic insulin receptors than do lean rats. Using similar numbers of wheat germ agglutinin-agarose (WGA)-purified insulin receptors with similar affinities for insulin, it was found that basal and insulin-stimulated phosphorylation of the synthetic tyrosine-specific kinase substrate poly(Glu, Tyr)4:1 was similar in lean and obese rats fed sucrose or starch. It is suggested that the contribution of the liver to the insulin resistance in obese SHR/N-cp rats probably lies distal to the insulin receptor tyrosine kinase.
Animals↗
Regulation by fasting of rat insulin-like growth factor I and its receptor. Effects on gene expression and binding.
We have examined, in liver and extrahepatic tissues, the effects of fasting on total insulin-like growth factor I (IGF-I) mRNA levels, on levels of different IGF-I mRNAs generated by alternative splicing of the primary IGF-I transcript, and on IGF-I receptor binding and mRNA levels. A 48-h fast decreased total IGF-I mRNA levels by approximately 80% in lung and liver, approximately 60% in kidney and muscle, and only approximately 30-40% in stomach, brain, and testes. In heart, IGF-I mRNA levels did not change. The levels of the different splicing variants, however, were essentially coordinately regulated within a given tissue. Specific 125I-IGF-I binding in lung, testes, stomach, kidney, and heart was increased by fasting by approximately 30-100%, whereas in brain 125I-IGF-I binding did not change in response to fasting. In tissues in which fasting increased IGF-I receptor number, receptor mRNA levels increased approximately 1.6- to 2.5-fold, whereas when IGF-I receptor number was unchanged in response to fasting, receptor mRNA levels did not change. These data demonstrate that the change in IGF-I and IGF-I receptor mRNA levels during fasting is quantitatively different in different tissues and suggest that regulation of IGF-I and IGF-I receptor gene expression by fasting is discoordinate.
Animals↗