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Biomedical subjects

C A Rossi

Publications and source records attributed to C A Rossi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Transmission of Crimean-Congo hemorrhagic fever virus by Hyalomma impeltatum (Acari:Ixodidae) after experimental infection.

We examined the potential for Hyalomma impeltatum Schulze & Schlottke ticks to transmit Crimean-Congo hemorrhagic fever (CCHF) virus. After feeding on 1-d-old mice that had been inoculated with CCHF virus, larval H. impeltatum became infected with and subsequently transmitted CCHF virus transstadially to nymphs. These nymphs transmitted virus horizontally to guinea pigs and transstadially to adults. A minimum of 13% of the adult H. impeltatum, exposed to virus as larvae, transmitted virus by bite to guinea pigs. An enzyme-linked immunosorbent assay detected CCHF viral antigen in 63% of the adult ticks derived from those exposed to this virus as larvae. This tick species should be considered as a potential vector of CCHF virus.

Animals↗
PubMed1996

Short report: lack of virus replication in arthropods after intrathoracic inoculation of Ebola Reston virus.

To evaluate the potential for arthropods to serve as reservoir hosts of Ebola virus, three mosquito species, Aedes albopictus, Aedes taeniorhynchus, and Culex pipiens, and a soft tick, Ornithodoros sonrai, were inoculated with 1O2.5 plaque-forming units of Ebola Reston virus. After incubation at 22 degrees C for 11 days, at least six specimens of each species were triturated and examined for evidence of viral replication by enzyme-linked immunosorbent assay and plaque assay. There was no evidence of viral replication in any of the arthropods tested. Because intrathoracic inoculation bypasses various barriers to viral infection, the lack of replication of Ebola Reston virus in these inoculated arthropods indicates that these mosquito species and soft ticks probably are not involved as natural reservoirs of Ebola virus.

Aedes↗
PubMed1995

Essential fatty acid metabolism in cultured rat cardiomyocytes in response to either N-6 or N-3 fatty acid supplementation.

In this study we demonstrate that cultured rat cardiomyocytes possess the capacity to desaturate/elongate essential fatty acids (EFAs). Alpha-linolenic acid (ALA) conversion to higher metabolites was greater than linoleic acid (LA) conversion, according to the higher affinity of the delta-6-desaturase enzyme for the n-3 than for the n-6 EFAs. Gamma-linolenic acid (GLA) supplementation to the culture medium had no influence on LA conversion; but the addition of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids significantly decreased the formation of interconversion products from LA. The conversion of ALA to higher metabolites was greatly affected by GLA; EPA had no effect on ALA conversion, while DHA significantly inhibited it. Both GLA (converted mostly to dihomo-gamma-linolenic acid) and EPA can be removed from phospholipids and addressed to prostanoid biosynthesis, so avoiding their potential accumulation and the inhibition of their own production. Our data clearly indicate that supplementation of the culture medium with either n-6 or n-3 fatty acids can cause reduced levels of the other series of fatty acids. This effect may be undesirable, since both n-6 and n-3 fatty acids are important in the prevention of coronary diseases.

Animals↗
PubMed1995

Phosphatidylinositol metabolism in lymphocytes of chronic alcoholic patients after anti-CD3 stimulation.

The immunological alterations observed in chronic alcoholic patients may be due to alterations of signal transduction across the lymphocyte membrane. Upon binding of mitogens or antigens to specific plasma membrane receptors, the activation of phospholipase C leads to the hydrolysis of inositol phospholipids, producing inositol phosphates and diacylglycerol. One of the early events in lymphocyte activation is an increase of intracellular calcium concentration, due to both an influx from extracellular fluid and a release from intracellular stores mediated by inositol phosphates. In this study we verified whether the diminished mobilization of intracellular calcium, previously observed in alcoholics, is caused by alteration in phosphoinositide turnover. We evaluated total inositol phosphate production in peripheral blood lymphocytes after anti-CD3 stimulation, comparing control subjects and alcoholic patients. Lymphocyte activation generated inositol phosphates in both controls and alcoholics, but to a different extent, inositol phosphate production being significantly higher in controls than in alcoholics. This reduction in inositol phosphate production could be accounted either to an inhibition of PLC activity or to a modified affinity of phospholipase C for its own substrates, i.e., phosphoinositides, which fatty acid composition has been previously demonstrated to be greatly different in alcoholics in comparison to healthy subjects.

Adult↗
PubMed1995

Short report: prevalence of hantavirus infection in rodents associated with two fatal human infections in California.

Rodents living near two fatal human cases of hantavirus pulmonary syndrome in California were surveyed for evidence of hantavirus infection. Seventeen (15%) (14 Peromyscus maniculatus and one each of P. truei, Eutamias minimus, and Microtus californicus) of 114 rodents tested had evidence (enzyme-linked immunosorbent assay or polymerase chain reaction) of hantavirus infection. This suggests that Peromyscus mice, and P. maniculatus in particular, may be the reservoir for the virus causing this newly recognized disease in California, as previously reported for New Mexico and Arizona.

Adult↗
PubMed1994

Dynamic of alpha-1-adrenoceptor mediated degradation of membrane phospholipids in cultured rat cardiomyocytes.

In many cell types, agonists can stimulate both phosphoinositide (PtdIns) and phosphatidylcholine (PC) hydrolysis by activating specific phospholipases. Using cultures of neonatal rat cardiomyocytes we have verified the existence of an alpha 1-adrenoceptor mediated hydrolysis of PtdIns and PC. PtdIns breakdown, evaluated as inositol phosphate production, occurred in the early phase of cell stimulation, while PC hydrolysis, evaluated as choline metabolite production, was evidenced at longer stimulation times. The appearance of a delayed peak of choline phosphate and the invariance of free choline in the intracellular water phase strongly suggest the involvement of a specific PC-phospholipase C, generating choline phosphate and diacylglycerol, the activator of protein kinase C. Since it is plausible that various metabolites of signal-induced degradation of membrane phospholipids may take part in long term physiological responses, PC breakdown could be involved in cellular mechanisms that require prolonged protein kinase C activation.

Animals↗
PubMed1994

Antigenic and molecular characterization of hantavirus isolates from China.

Hemorrhagic fever with renal syndrome (HFRS) is caused by certain viruses in the genus Hantavirus, family Bunyaviridae, and is a major public health problem in China. By using molecular and serological tests, we characterized 15 hantaviruses isolated either from patients with HFRS or from rodents captured in endemic areas of China. By cross plaque-reduction neutralization tests performed with rabbit immune sera, we identified two serologically distinct groups of viruses, comprised of those related to Hantaan virus, and those related to Seoul virus. To study the genetic relationships among these viruses, we amplified a 330 base pair region of the medium (M) genome segment of each isolate by reverse transcription and polymerase chain reaction (PCR) and compared the nucleotide sequences to those of other, well-characterized hantaviruses. In addition, we PCR-amplified and analyzed the entire coding region of the small (S) genome segment of each isolate by restriction enzyme digestion with a battery of enzymes. The results of our genetic analyses of both the M and S segments of these isolates confirmed our serological data, indicating that Hantaan and Seoul viruses co-circulate in endemic disease regions of China. We constructed a phylogenetic tree based on multiple alignment of the partial M segment sequences. The resulting dendrogram distinguished three genetic subtypes of Hantaan viruses and one type of Seoul virus.

Animals↗
PubMed1994

Isolation of a Puumala-like virus from Mus musculus captured in Yugoslavia and its association with severe hemorrhagic fever with renal syndrome.

An outbreak of severe hemorrhagic fever with renal syndrome (HFRS) occurred in 1988 in Pozarevac, Serbia, Yugoslavia. The disease was diagnosed in 4 children and 1 adult, and 1 of the children died. Rodents were captured from the same area and virus isolation attempted. A hantavirus, POZ-M1, was isolated from lung tissues of hantavirus antigen-positive Mus musculus. Serology and restriction enzyme digestion of polymerase chain reaction-amplified segments from this virus showed that it was a strain of Puumala (PUU) virus, the causative agent of nephropathia epidemica. While Clethrionomys glareolus is the major rodent host for PUU virus, these results suggest that M. musculus may also play an important role in harboring and transmitting PUU-like viruses. The serologic association of this virus with patients with severe HFRS reaffirms that PUU-like viruses may cause severe disease in addition to the generally mild form normally associated with nephropathia epidemica.

Animals↗
PubMed1994

Serologic and virologic evidence of a Prospect Hill-like hantavirus in Wisconsin and Minnesota.

The purposes of this study were to determine if hantaviruses were present in the Great Lakes port areas of Wisconsin and Minnesota and if so, to identify which virus and which rodent host species were involved. Rodents were trapped in Duluth, Minnesota, Superior, Green Bay, and Milwaukee, Wisconsin, all ports of call for international maritime shipping. A total of 675 wild rodents were captured and tested, including 310 meadow voles (Microtus pennsylvanicus), 173 Norway rats (Rattus norvegicus), 179 Peromyscus spp., (including white footed mice [P. leucopus] and deer mice [P. maniculatus gracilis and P. maniculatus bairdii]), and 13 house mice (Mus musculus). Twenty percent of the rats, 17% of the meadow voles, 8% of the house mice, and 3% of the Peromyscus spp. had antibody to a hantavirus by immunofluorescent antibody assay (IFA). By the plaque-reduction neutralization test (PRNT), nine of 36 meadow voles, one of 4 P. leucopus, and one of 34 rats had hantavirus antibody, with the highest titers to Prospect Hill (PH) virus. All of the PRNT-seropositive individuals were from the twin cities of Superior and Duluth. Hantavirus antigen was detected in lung tissue by IFA in M. pennsylvanicus and Peromyscus spp., but not in rats. Two hantaviruses, designated SD-1 and SD-2, were isolated from M. pennsylvanicus captured in Duluth and found to be very similar to prototype PH virus by cross-IFA and cross-PRNT. Virus isolation attempts were unsuccessful from tissues of the Peromyscus spp. and the rats.

Animals↗
PubMed1993

Purification and partial characterization of a mitogenic lectin from the latex of Euphorbia marginata.

A lectin was purified from the latex of Euphorbia marginata by affinity chromatography on acid-treated Sepharose 6B and elution with lactose. The lectin is a glycoprotein composed of two identical subunits with M(r) 30,000, approx. The haemagglutinating activity of the lectin is not specific for any human blood group, and is inhibited by galactose and galactose-containing sugars and by gentiobiose. The lectin is strongly mitogenic for human T-lymphocytes and induces the release of interleukin-1 beta and tumor necrosis factor-alpha from cultured mononuclear cells.

Adult↗
PubMed1993

Evidence for a detectable delta-6-desaturase activity in rat heart microsomes: aging influence on enzyme activity.

This study represents the first report indicating that rat heart microsomes contain a measurable delta-6-desaturase activity. The aging process affects delta-6-desaturase activity in the heart to a lesser extent than in the liver, supporting the hypothesis that the regulation of the individual desaturase enzymes may differ in these two tissues. Although decreased desaturase activity, considered alone, may be expected to lower polyunsaturated fatty acid levels, in old animals no modifications in heart microsome fatty acid composition were observed. Probably other metabolic changes may offset this effect, leading to the maintenance of arachidonic acid level in the heart.

Aging↗
PubMed1993

In vivo effect of chronic ethanol consumption on the fatty acid composition of phosphatidylinositols in resting and anti-CD3-activated lymphocytes.

Fatty acid composition of phosphatidylinositols was analyzed in peripheral blood lymphocytes from nine alcoholic patients who were well nourished and without severe acute and chronic liver disease, before and after stimulation with anti-CD3 antibody. Six comparable nondrinkers were studied as controls. A reduction in unsaturated fatty acid (mainly arachidonic) and an increase in palmitic and stearic acid molar content were observed in phosphatidylinositol (PI), phosphatidylinositol-4-phosphate (PIP), and phosphatidylinositol-4,5-bisphosphate (PIP2) in unstimulated samples from alcoholic patients in comparison with normal subjects, leading to a significant decrease in the saturated/unsaturated ratio. In controls, anti-CD3 stimulation caused a marked decrease in arachidonic acid relative molar content counterbalanced by an increase in other polyunsaturated fatty acid relative molar content in PI, PIP, and PIP2 fractions. Interestingly, after anti-CD3 stimulation, alcoholic patients show the same trend of modification in the fatty acid composition resulting in a sharp reduction of arachidonic acid relative molar content. These results support the hypothesis of an alteration in nutrients being responsible for immune derangement in alcoholics.

Adult↗
PubMed1993

Fe3+ binding to liposomes of different phospholipid composition.

The possibility that phospholipid polar heads may influence lipid peroxidation by affecting the binding and location of the metal catalyst was investigated. The multilamellar liposomes containing dimyristoyl phosphatidylcholine (DMPC) and an equal amount of either dipalmitoyl phosphatidylcholine (DPPC) or dipalmitoyl phosphatidic acid (DPPA) were utilized to study Fe3+ location. Two simple colorimetric methods were utilized, which were developed to evaluate: a) Fe3+ both sequestered within and bound in a non reducible form on the surface of the liposomes; Fe3+ chelated to strong complexing agents present both on the surface and in the inner compartment of the liposomes. The results obtained clearly show that the two types of polar heads differently bind the metal. Whereas DMPC/DPPC liposomes do not affect Fe3+ detection by both methods, suggesting that the metal is not internalized and strongly bound, DMPC/DPPA liposomes greatly interfere with Fe3+ detection. Analysis of the binding data indicates that a large amount of the metal is sequestered by the liposomes both in a complexed and free form.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1992

Protein kinase C activity in neonatal cultured rat cardiomyocytes supplemented with docosahexaenoic acid.

In vitro studies have indicated that the 1-stearoyl, 2-arachidonyl diacylglycerol (DAG) is the most effective one for the activation of protein kinase C, although many other DAGs having a different fatty acid composition are active, but to a different extent. Using cultures of neonatal rat ventricular cells, grown in a medium enriched in docosahexaenoic acid (DHA), we previously obtained a cell population that, after alpha 1-adrenoceptor stimulation, produced a DHA enriched DAG. In this study, we have tested the "in vivo" ability of this modified DAG as protein kinase C activator, demonstrating a lower but more persistent translocation of the enzyme from cytosol to particulate fraction in the DHA treated cells. The differences in the PKC activation pattern could be explained by a different metabolism of the DHA enriched DAG by DAG kinase.

Animals↗
PubMed1992

Measurement of glycated proteins in human plasma or murine hepatic cytosolic fractions by a competitive enzyme linked immune assay (ELISA).

After planned immunization, a rabbit polyclonal antibody has been produced that recognized the Schiff base moiety of glycated proteins. Using an ELISA technique, antiserum specifically recognized reduced and glycated epitopes on a variety of proteins, and did not react with nonreduced and glycated proteins. The antiserum showed very low cross-reactivity with reduced but not glycated proteins. The assay was also used to determine the degree of ex vivo glycation of serum proteins from diabetic patients or hepatic cytosolic proteins from mice. Thus, this assay may be used to determine the amount of in vitro or ex vivo glycation of blood or tissue proteins.

Animals↗
PubMed1992

[The correlation between the acidic composition of diacylglycerol and protein kinase C activation in cultures of rat cardiomyocytes].

We have studied the fatty acid composition of the diacylglycerol produced after different stimulation times with an alpha 1-agonist (phenylephrine) in cultures of beating neonatal rat cardiomyocytes, and we have related the acidic pattern to the time course of the translocation of protein kinase C from cytosol to the membrane, both in control cells and in cells grown in a medium supplemented with docosahexaenoic acid. Gas chromatography of the diacylglycerol produced after stimulation revealed significant differences between control cells and cells grown in the docosahexaenoic acid supplemented medium. In the control cells, in the early stimulation times, the higher protein kinase C activity was due to a higher relative molar content of arachidonic acid in the diacylglycerol; in the docosahexaenoic acid treated cells the lower but more persistent activation of the membrane-bound protein kinase C might be sustained by an enrichment of diacylglycerol with docosahexaenoic acid. The modification of the fatty acid composition of diacylglycerol can cause an alteration in the response of the cells to alpha 1-adrenoceptor stimulation.

Animals↗