Persistent platelet activation in patients with type 2 diabetes treated with low doses of aspirin.

BACKGROUND: The percentage of diabetic patients who do not benefit from the protective effect of aspirin is larger than in other populations at cardiovascular risk. OBJECTIVE: We compared the ability of aspirin to suppress TxA2 and platelet activation in vivo, in type-2 diabetics vs. high-risk non-diabetic patients. METHODS: Urinary 11-dehydro-TXB2, plasma sCD40 L, and sP-selectin were measured, together with indices of low-grade inflammation, glycemic control, and lipid profile, in 82 patients with type-2 diabetes and 39 without diabetes, treated with low doses of aspirin. RESULTS: Urinary 11-dehydro-TxB2, plasma sCD40L and sP-selectin were significantly higher in diabetics than in controls: [38.9 (27.8-63.3) vs. 28.5 (22.5-43.9) ng mmol(-1) of creatinine, P = 0.02], [1.06 (0.42-3.06) vs. 0.35 (0.22-0.95) ng mL(-1); P = 0.0001], [37.0 (16.8-85.6) vs. 20.0 (11.2-35.6) ng mL(-1), P = 0.0001], respectively. The proportion of individuals with diabetes increased across quartiles of 11-dehydro-TxB2, sCD40L, and sP-selectin, with the highest quartiles of 11-dehydro-TxB2, sCD40L and sP-selectin, including 66%, 93.3%, and 93.3% of individuals with diabetes. Markers of platelet activation positively correlated with indices of glycemic control but not with markers of low-grade inflammation. CONCLUSIONS: Platelet dysfunction associated with insufficient glycemic control, may mediate persistent platelet activation under aspirin treatment.

Multiple cyclic AMP receptors are linked to adenylyl cyclase in Dictyostelium.

cAMP receptor 1 and G-protein alpha-subunit 2 null cell lines (car1- and g alpha 2-) were examined to assess the roles that these two proteins play in cAMP stimulated adenylyl cyclase activation in Dictyostelium. In intact wild-type cells, cAMP stimulation elicited a rapid activation of adenylyl cyclase that peaked in 1-2 min and subsided within 5 min; in g alpha 2- cells, this activation did not occur; in car1- cells an activation occurred but it rose and subsided more slowly. cAMP also induced a persistent activation of adenylyl cyclase in growth stage cells that contain only low levels of cAMP receptor 1 (cAR1). In lysates of untreated wild-type, car1-, or g alpha 2- cells, guanosine 5'-O-'(3-thiotriphosphate) (GTP gamma S) produced a similar 20-fold increase in adenylyl cyclase activity. Brief treatment of intact cells with cAMP reduced this activity by 75% in control and g alpha 2- cells but by only 8% in the car1- cells. These observations suggest several conclusions regarding the cAMP signal transduction system. 1) cAR1 and another cAMP receptor are linked to activation of adenylyl cyclase in intact cells. Both excitation signals require G alpha 2. 2) cAR1 is required for normal adaptation of adenylyl cyclase. The adaptation reaction caused by cAR1 is not mediated via G alpha 2. 3) Neither cAR1 nor G alpha 2 is required for GTP gamma S-stimulation of adenylyl cyclase in cell lysates. The adenylyl cyclase is directly coupled to an as yet unidentified G-protein.

Impaired left ventricular diastolic function and vascular postischemic vasodilation associated with microalbuminuria in IDDM patients.

OBJECTIVE: Microalbuminuria is considered an important predictor of cardiovascular events in diabetic patients. In this study, a possible association of microalbuminuria with significant changes in left ventricular (LV) morphology and function and generalized vascular dysfunction was analyzed in insulin-dependent diabetes mellitus (IDDM) patients without hypertension, coronary artery disease, or autonomic dysfunction. RESEARCH DESIGN AND METHODS: Thirty-four young long-term IDDM patients, 16 with and 18 without microalbuminuria, and 20 control subjects were studied. LV systolic function and wall thickness were evaluated by M-mode echocardiography. LV diastolic function was studied using a combined echo-Doppler and phonocardiographic technique. The hyperemic response to forearm ischemia was measured by strain-gauge plethysmography. All patients underwent 24-h ambulatory blood pressure monitoring. RESULTS: LV mass index and wall thickness:radius ratio were significantly higher in microalbuminuric patients. LV relaxation was significantly impaired in both diabetic groups compared with control subjects; moreover, this impairment was significantly greater in microalbuminuric than in normoalbuminuric patients. In microalbuminuric patients, forearm postischemic vasodilation was also significantly lower and mean awake diastolic blood pressure (dBP) was significantly higher than in the other two groups. CONCLUSIONS: Our data suggest that microalbuminuria is associated with significant changes in LV morphology, a more severe impairment of cardiac diastolic function, altered vascular dilatory capacity, and higher daytime dBP. Therefore, microalbuminuric patients should be considered to have a higher risk of cardiovascular complications and be kept under closer surveillance.

[Percutaneous renal biopsy in children: use of a fine needle]. / Biopsia renale percutanea in età pediatrica: uso di un ago sottile.

Percutaneous renal biopsies were performed on native kidneys in 40 children and adolescent, aged 1.7-13 (mean 6.7) years. Bleeding diatheses were excluded by the determination of Hb, blood platelets, PT, PTI and fibrinogen. Biopsies were performed under ultrasound imaging, using a semiautomated and thin needle (20 gauge in children with age under 5 years and 18 gauge for those over 5 years). All the patients were lightly sedated, except for 3 ones who received a general anesthesia. Diagnostically adequate tissue was retrieved in 38 of 40 biopsy procedures (95%). A macro-haematuria was observed with elimination of haematic coagula in 3 children (7.5%) and 24-h post-biopsy ultrasonography disciosed a small haematoma of the biopsied kidney in 2 one (5%). No mayor complications occurred. We conclude that the use of ultrasound imaging and a semiautomated needle is a safe and efficient method for performing renal biopsies in paediatric patients. The use of smaller (18 or 20-gauge) cutting needles would reduce the complications rate while allowing retrieval of sufficient tissue for histologic diagnosis.

[Hereditary blood anomalies in the Abruzzi population in Valle del Sangro: from hematologic genetics to the history of a population]. / Le anomalie ereditarie del sangue nella popolazione abruzzese della valle del Sangro: dalla genetica ematologica alla storia di una popolazione.

A high incidence of hereditary blood anomalies (particularly Pelger-Huët's congenital granulocytic anomaly and Lepore haemoglobinopathy) is reported in the people of the Sangro Valley (Abruzzo, South Italy). The clinical, haematological, genetic and demographic implications of the high incidence of these pathologies are discussed.

[Sick sinus syndrome probably caused by cardiac metastases]. / Sindrome del seno malato da probabile metastasi cardiaca.

A case of Sick Sinus Syndrome probably secondary to cardiac metastasis in a patient affected by metastatic breast cancer is described. The diagnostic and etiopathogenetic aspects in the case under examination are also discussed.

[Monoclonal gammopathies in the aged]. / Le gammapatie monoclonali nell'età senile.

60 cases of monoclonal (benign and malignant) are presented. All the patients are divided into two sub-groups according to the age (until and after 65th years old). They were recovered in the Medical and Geriatric divisions of "Renzetti" civic Hospital in Lanciano. The differences between the two groups with respect to different types of gammapathy, median survival rates, response to therapy, are discussed.

[Multiple neoplastic combinations in the aged. Case contribution]. / Associazioni multiple neoplastiche nell'anziano. Contributo casistico.

Four cases of patients suffering from more than one type of neoplasia are described. Plasmocytoma was found in three of the four cases. Links between old age, cancer and immunity are put forward in relation to the geriatric age of the four patients.

[Transitory bisalbuminemia secondary to pancreatitis with ascitic effusion]. / Bisalbuminemia transitoria secondaria a pancreatite con versamento ascitico.

A case of transient bisalbuminemia secondary to pancreatitis with ascites is described. The bisalbumin was of the "fast" type and disappeared after sixty days of therapy. The clinical and pathological implications of these findings are discussed.

Reye's syndrome and aspirin use: a possible immunological relationship.

Reye's syndrome is a serious childhood disease usually associated with an antecedent viral illness such as influenza or chicken pox. Recent reports indicate a relationship between moderate aspirin use during the viral infection and the development of Reye's disease. The blastogenic response of cultured lymphocytes to lectins mimics their in vivo response to viral antigens. We report here that physiological doses of the cyclooxygenase inhibitor aspirin, induce marked hyperactivity in this response. Mouse spleen lymphocyte cultures were treated with phytohemagglutinin (PHA) and mitogenesis was assayed after 72 hours by measuring incorporation of 3H thymidine. Addition of aspirin produced up to 3-fold increases in the PHA response. The effect was specific for T-lymphocytes and response to the B lymphocyte mitogen LPS was not significantly affected. The hyperproliferative effect was dose-dependent being maximum at aspirin levels of 300-400 microM and was reversed by addition of prostaglandin E2 (10-9M). Maximum effects were observed when aspirin was added to cells within 8-10 hours of exposure to antigen. The observations suggest that Reye's syndrome may result from an aspirin-induced aberration in the immune response to a viral infection.

Inhibition of phytohemagglutinin-induced lymphocyte mitogenesis by lipoxygenase metabolites of arachidonic acid: structure-activity relationships.

Phytohemagglutinin (PHA)-induced mitogenesis of mixed mouse spleen lymphocyte populations, measured by [3H]thymidine incorporation, was completely inhibited by micromolar concentrations of certain hydroxyeicosatetraenoic acids (HETE's). These are lipoxygenase metabolites of arachidonic acid which are synthesized in considerable concentrations by macrophages, lymphocytes, and other components of the immune system when appropriately stimulated. In the studies described here, the structural requirements for the maximum antimitogenic activities were examined. A series of monohydroxylated HETE's were prepared using a singlet oxygen photochemical procedure or by enzymatic synthesis from arachidonic acid substrate, and isolated by HPLC. Isomers containing different numbers of double bonds were synthesized using the appropriate unsaturated fatty acid as substrate, and the functional importance of the OH and carboxylic functions was tested using various acetoxy- and carbomethoxy derivatives. A serum-free mitogenesis assay system was used for testing, which minimized binding of the fatty acids by serum proteins and increased the inhibitory potency of the various HETE's several-fold. It was found that inhibition of cell proliferation was related to: hydroxyl proximity to the center of the eicosatetraenoic acid, decreasing in the order: 9 greater than 11 greater than 12 greater than 15 greater than 8 much greater than 5; the number of double bonds in the fatty acid chain, decreasing in the order: 15-OH, 20:4 greater than 15-OH 20:3 much greater than 15-OH, 20:2 much greater than 15-OH, 20:0; and the 15-position functional group as well as the 1-carboxylic group, decreasing in the order: 15-hydroxy, 1-carboxylic greater than 15-acetoxy, 1-carboxylic much greater than 15-hydroxy, 1-carbomethoxy greater than 15-acetoxy, 1-carbomethoxy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Neonatal gastric obstruction]. / L'ostruzione gastrica neonatale.

Gastric outlet obstruction in newborn may be due to segmental atresia or mucosal diaphragm. The authors report two cases of pyloric obstruction and they consider the etiopathogenetic and diagnostic aspects.

Molecular genetic analysis of two G alpha protein subunits in Dictyostelium.

In Dictyostelium, chemotaxis to folate during growth and cAMP during aggregation is controlled via cell surface receptors. To study the role of two G alpha proteins (G alpha 1 and G alpha 2) in these responses, we examined the physiological and biochemical effects of null mutations caused by antisense mutagenesis and gene disruptions. Disruption of G alpha 2 results in an aggregation-deficient phenotype and a loss of cAMP receptor-mediated functions, including activation of adenylate cyclase, guanylate cyclase, and gene expression and in a loss of GTP-mediated decrease in receptor affinity for cAMP, but it has no effect on chemotaxis to folate or folate activation of guanylate cyclase. These phenotypes can be rescued by a vector expressing G alpha 2, suggesting G alpha 2 is coupled to a cAMP receptor but not to folate receptors. Loss of G alpha 1 expression resulted in no visible growth or developmental phenotype, including cAMP- and folate-stimulated responses, suggesting G alpha 1 function is either not essential under standard laboratory conditions or is encoded by multiple genes. Availability of null mutations provides suitable genetic backgrounds for expressing mutant G alpha protein subunits which can then be used to examine the physiological roles of G alpha 1 and G alpha 2. Construction of these gene disruptions was facilitated by using the auxotrophic marker THY1, which allowed for selection of single-copy insertions into the genome.

Multiple alpha subunits of guanine nucleotide-binding proteins in Dictyostelium.

Previous results have shown that chemotaxis and the expression of several classes of genes in Dictyostelium discoideum are regulated through a cell surface cAMP receptor interacting with guanine nucleotide-binding proteins (G proteins). We now describe cloning and sequencing of cDNAs encoding two G alpha protein subunits from Dictyostelium. The derived amino acid sequences show that they are 45% identical to each other and to G alpha protein subunits from mammals and yeast. Both cDNAs are complementary to multiple mRNAs that are differentially expressed during development. This evidence and analysis of mutants presented elsewhere suggest that they have distinct physiological functions.

Immunological detection of G-protein alpha-subunits in Dictyostelium discoideum.

Putative G-protein alpha-subunits in Dictyostelium discoideum were detected on western blots using the antiserum A-569, raised against a peptide whose sequence is found in alpha-subunits of all known GTP-binding signal transducing proteins. Two bands with a MW of 40 kDa and 52 kDa were specifically recognized by the common peptide antiserum; the staining of both bands was strongly reduced when the antiserum was preincubated with the peptide that was used for antibody production. D.discoideum mutant HC213 (fgd A) lacks staining of the 40 kDa band, while the 52 kDa band is still present. This mutant is severely defective in cAMP receptor-G-protein interaction. We concluded that the primitive eukaryote D.discoideum contains proteins which show functional and physical similarity with the alpha-subunits of vertebrate G-proteins.

Regulation and function of G alpha protein subunits in Dictyostelium.

We have examined the developmental regulation and function of two G alpha protein subunits, G alpha 1 and G alpha 2, from Dictyostelium. G alpha 1 is expressed in vegetative cells through aggregate stages while G alpha 2 is inducible by cAMP pulses and preferentially expressed in aggregation. Our results suggest that G alpha 2 encodes the G alpha protein subunit associated with the cAMP receptor and mediates all known receptor-activated intracellular signal transduction processes, including chemotaxis and gene regulation. G alpha 1 appears to function in both the cell cycle and development. Overexpression of G alpha 1 results in large, multinucleated cells that develop abnormally. The central role that these G alpha proteins play in signal transduction processes and in controlling Dictyostelium development is discussed.