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Biomedical subjects

R R Rosato

Publications and source records attributed to R R Rosato.

18 recordsLinked to original sources
PubMed2004

Potent antileukemic interactions between flavopiridol and TRAIL/Apo2L involve flavopiridol-mediated XIAP downregulation.

Interactions between the cyclin-dependent kinase inhibitor flavopiridol (FP) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL/Apo2L), were examined in human leukemia cells (U937 and Jurkat). Coexposure of cells to marginally toxic concentrations of TRAIL and FP (24 h) synergistically increased mitochondrial injury (eg, cytochrome c, AIF, Smac/DIABLO release), cytoplasmic depletion of Bax, activation of Bid as well as caspase-8 and -3, PARP cleavage, and apoptosis. Coadministration of TRAIL markedly increased FP-induced apoptosis in leukemic cells ectopically expressing Bcl-2, Bcl-x(L), or a phosphorylation loop-deleted form of Bcl-2 (DeltaBcl-2), whereas lethality was substantially attenuated in cells ectopically expressing CrmA, dominant-negative-FADD, or dominant-negative-caspase-8. TRAIL/FP induced no discernible changes in FLIP, DR4, DR5, Mcl-1, or survivin expression, modest declines in levels of DcR2 and c-IAP, but resulted in the marked transcriptional downregulation of XIAP. Moreover, cells stably expressing an XIAP-antisense construct exhibited a pronounced increase in TRAIL sensitivity comparable to degrees of apoptosis achieved with TRAIL/FP. Conversely, enforced XIAP expression significantly attenuated caspase activation and TRAIL/FP lethality. Together, these findings suggest that simultaneous activation of the intrinsic and extrinsic apoptotic pathways by TRAIL and FP synergistically induces apoptosis in human leukemia cells through a mechanism that involves FP-mediated XIAP downregulation.

Apoptosis↗
PubMed2001

Evidence of a functional role for the cyclin-dependent kinase-inhibitor p21WAF1/CIP1/MDA6 in promoting differentiation and preventing mitochondrial dysfunction and apoptosis induced by sodium butyrate in human myelomonocytic leukemia cells (U937).

The impact of dysregulation of the cyclin-dependent kinase inhibitor p21WAF1/CIP1/MDA6 has been examined in U937 human monocytic leukemia cells in relation to cell cycle arrest and differentiation following treatment with the histone deacetylase inhibitor sodium butyrate (SB). Cells stably transfected with a p21WAF1/CIP1/MDA6 antisense construct, in marked contrast to their wild-type counterparts, failed to up-regulate p21WAF1/CIP1/MDA6, undergo G1 arrest, or express the maturation marker CD11b when exposed to 1 or 3 mM SB. However, antisense-expressing cells were significantly more susceptible to SB-mediated mitochondrial injury and apoptosis, manifested by increased cytosolic translocation of cytochrome c, activation of pro-caspase 3, and degradation of PARP. Dysregulation of p21WAF1/CIP1/MDA6 did not modify the extent of SB-induced histone acetylation, but did result in cleavage of p27KIP1, Bcl-2 and pRb, as well as diminished levels of full-length underphosphorylated pRb. Finally, dysregulation of p21WAF1/CIP1/MDA6 did not modify SB-mediated down-regulation of E2F-1 or c-Myc, but was associated with enhanced down-regulation of cyclins D1 and E. Together, these findings indicate that in U937 leukemia cells, p21WAF1/CIP1/MDA6 plays a critical functional role in SB-mediated G1 arrest and maturation, and suggest that cells displaying dysregulation of this CDKI respond to SB by engaging a default apoptotic program.

Apoptosis↗
PubMed1998

mRNA expression patterns of the IGF system during mouse limb bud development, determined by whole mount in situ hybridization.

During limb development the primary limb bud requires various signals to differentiate. Insulin-like growth factor (IGF)-I and IGF-II serve as ubiquitous cellular growth promoters and are modulated by their binding proteins (IGFBPs), which inhibit or augment IGF bioavailability. This is the first study to give a complete overview of the mRNA expression patterns of Igf-1, Igf-2, type 1 Igf receptor (Igf1r) and six Igf binding proteins (IGFBP-1-6) in embryonic mouse limbs, at various stages of development, by whole mount in situ hybridization (ISH). Our results show that all the members of the Igf system, except Igfbp-1 and -6, have specific spatio-temporal mRNA expression patterns. IGFBP-2 and -5 are found in the apical ectodermal ridge (AER), and IGF-I and IGFBP-4 in the region of the zone of polarizing activity (ZPA). IGF-II and IGF1R are found in regions of pre-cartilage formation. At 13.5 days post coitus (dpc) the IGF system colocalizes with apoptosis areas; IGFBP-2, -4 and -5 are found in the interdigital zone, while IGFBP-3 and IGF-I border this region. Furthermore, IGFBP-3, -4 and -5 are found in the phalangeal joint areas, at an early stage of joint formation. This supports the hypothesis that the IGF system may be involved in chondrogenic differentiation of mesenchyme and the regulation of apoptosis in the developing limb.

Animals↗
PubMed1998

Effect of chronic thyroxine treatment on pregnancy in rats: effects on oestrogen, progesterone, prolactin and GH receptors in uterus, liver and mammary gland.

We have previously shown that experimental hyperthyroidism produces premature and difficult delivery and absence of lactation in spite of apparently adequate luteolysis and lactogenesis. To study the possible causes of these alterations we measured the effect of treatment with T4 (0.25 or 1 mg kg(-1), s.c., daily, started 10-15 days before mating, HT0.25 and HT1) on serum hormones and their receptor (R) concentrations in reproductive tissues on day 20 of pregnancy (1800 hours), comparing them with controls on the same day (C20), or on day 21 of pregnancy (1800 hours) (C21). Serum prolactin (PRL) and corticosterone (B) concentrations increased in the HT groups, progesterone (Pg) and GH decreased and estradiol (E2) did not change, compared with C20 group. C21 rats had increased serum PRL and decreased Pg and GH. In HT rats mammary DNA and protein tissue content was doubled. Receptor concentrations were expressed per mg DNA. Mammary PRL-R were increased in HT1 rats, while E-R and Pg-R were significantly lower in both HT groups. HT0.25 and HT1 rats had increased uterine E-R and Pg-R and decreased liver PRL-R and GH-R as well as their mRNAs. Liver E-R, PRL-R and GH-R were decreased in C21 rats, while uterine Pg-R were increased. Thus, some of the observed changes (serum Pg and GH, mammary and uterine Pg-R, and liver GH-R and PRL-R decreases and serum PRL increase) may be due at least partially to the advancement in luteolysis and delivery, being similar to the changes observed between days 20 and 21. The changes in serum B, mammary PRL-R, and mammary and uterine E-R may be caused solely by the T4 treatments and may play a role in the alterations previously observed.

Animals↗
PubMed1997

Gene expression of the insulin-like growth factor system during mouse kidney development.

Expression of the insulin-like growth factor (IGF) system was investigated in mouse renal development and physiology, using non radioactive in situ hybridization and quantitative RT-PCR. IGF-I mRNA levels increased after birth and were confined to distal tubules and peritubular capillaries in the outer medulla. IGF-II mRNA levels were high in developing kidneys and peaked after birth. The type I receptor mRNA expression pattern mostly parallelled those of IGF-I and IGF-II. The IGF binding proteins (IGFBP's) showed weak mRNA expression for IGFBP-1 and -6. High fetal mRNA levels were measured for IGFBP-2, showing a similar profile in time as observed for IGF-II. Low fetal IGFBP-3 and -5 mRNA levels increased after birth. IGFBP-2, -4 and -5 mRNA expression was localized to differentiating cells. In the mature kidney predominant expression was confined to proximal tubules (IGFBP-4), thin limbs of Henle's Loop (IGFBP-2), glomerular mesangial cells (IGFBP-5) and peritubular capillaries of the medulla (IGFBP-5). IGFBP-3 mRNA was exclusively expressed in endothelial cells of the renal capillary system. Distinct mRNA expression for each member of the IGF system may point to specific roles in development and physiology of the mouse kidney.

Animals↗
PubMed1997

IGF, type I IGF receptor and IGF-binding protein mRNA expression in kidney and liver of potassium-depleted and normal rats infused with IGF-I.

Dietary potassium (K) depletion is known to reduce body weight gain and organ growth, except for kidney which increases in weight. This renal hypertrophy is preceded by increased renal IGF-I levels. In the present study, we investigated IGF-I and -II, type I IGF receptor and IGF-binding protein (IGFBP) mRNA expression in liver and kidney of K-depleted and normal rats infused with vehicle or recombinant human IGF-I. Body weight gain was almost completely arrested in K-depleted rats without any stimulatory effect of IGF-I infusion. Both absolute and relative kidney weight (kidney weight/body weight) were significantly increased in K-depleted rats and this was further enhanced by IGF-I infusion. In contrast, relative liver weight was comparable in the different groups and unaffected by IGF-I infusion. IGF-I mRNA expression was significantly lower in kidney and liver of K-depleted animals whereas type I IGF receptor levels were unchanged. In contrast, in kidney, K depletion increased IGFBP-1 and -2 mRNA expression with no additional effect of IGF-I infusion. In liver of K-depleted animals, IGFBP-1 mRNA expression was increased whereas increased IGFBP-1 and -2 mRNA expression was observed when these animals were infused with IGF-I. These observations may point towards a differential mode of action of the IGFBPs. In kidney increased IGFBP-1 and -2 mRNA expression may enhance IGF-I bioavailability with subsequent kidney growth. In liver, with clearly detectable type I IGF receptor mRNA expression, increased IGFBP levels may protect from IGF-I-induced organ growth by decreasing IGF-I bioavailability.

Animals↗
PubMed1992

Amelioration of some metabolic effects produced by hyperthyroidism in late pregnant rats and their fetuses. Effects on lipids and proteins.

We have studied the effect of 40-45 days administration of 1 mg/kg thyroxine on protein and lipid metabolism in liver, heart, lungs, kidneys and adrenal glands of virgin and 21-day pregnant rats and their fetuses and placentae. The chronic administration of thyroid hormone produced significant increases in serum T3 and T4 in both groups as well as in organ weights and protein concentrations in virgin rats, but much smaller modifications in pregnant ones. Hyperthyroidism decreased the weight of fetal livers and increased that of placentae; protein content was increased in all fetal organs. Hyperthyroidism induced increases in phospholipid concentrations in all the organs and in total lipids only in liver and heart of adult rats, which were not counteracted by pregnancy. Pregnant rats had increases in total lipids in liver and kidneys and in adrenal phospholipids. In hyperthyroid fetuses there was an increase in hepatic total lipids and no changes in phospholipids. Hepatic lipogenesis (measured by in vivo incorporation of 3H2O into lipids) was increased by hyperthyroidism in virgin and pregnant rats, but the increase was significantly smaller in the pregnant hyperthyroid rats compared with the virgin ones. Fetal lipogenesis in liver and lung was not changed. In addition, an increase was observed in lipogenic enzyme (fatty acid synthetase and glucose-6-phosphate dehydrogenase) activities in hyperthyroid virgin rats which was prevented by pregnancy. In fetuses only pulmonary glucose-6-phosphate dehydrogenase was increased when expressed in terms of tissue weight. Our results indicate that the metabolic effect of hyperthyroidism is attenuated in pregnant rats and their fetuses, when compared with adult virgin rats, in most of the parameters studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effects of chronic thyroid hormone administration on pregnancy, lactogenesis and lactation in the rat.

We studied the effects of daily administration of 1 mg/kg thyroxine (T4) starting 10-15 days before mating, on parturition, maternal behavior and lactation in rats. Treated rats had elevated serum titers of T3 and T4, a greater number of fetuses and parturition was advanced approximately 12 h and lasted longer than in controls. None of the treated rats were able to lactate because of defects in maternal behavior and milk ejection; the litters died usually within 48 h postpartum. In rats sacrificed at 10.00 on day 21 of pregnancy, mammary gland content of total protein, phospholipids, casein and lactose were significantly increased, but total lipid was markedly reduced. Lipogenesis was also significantly increased, as well as the activity of the lipogenic enzymes glucose-6-phosphate dehydrogenase, fatty acid synthetase and isocitrate dehydrogenase. These results are indicative of normal albeit premature lactogenesis. The T4-treated rats also had advances in the prepartum fall in serum progesterone and the increase in prolactin as well as in the increase in mammary casein and lactose concentrations of approximately 12 h with respect to control pregnant rats. These results show that chronic T4 treatment induces an advance of approximately 12 h in luteolysis, which in turn advances lactogenesis and parturition in rats. Although the mammary gland was able to produce milk, lactation failed due to abnormal maternal behavior and milk ejection, the causes of which are still unknown. Other effects of hyperthyroidism were also present, such as a severe reduction in lipid content of the gland.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Enzyme-linked immunosorbent assay detection of immunoglobulins G and M to Venezuelan equine encephalomyelitis virus in vaccinated and naturally infected humans.

Enzyme-linked immunosorbent assays (ELISAs) were developed for detection of immunoglobulin G (IgG) and IgM antibodies to Venezuelan equine encephalomyelitis (VEE) virus in vaccinated and naturally infected humans. A total of 441 sera found negative for VEE antibodies by plaque reduction neutralization were examined by IgG ELISA and gave a 1.0% false-positive rate; no false-positives were found in the IgM ELISA. Sera with neutralizing antibody to western or eastern equine encephalomyelitis virus did not react with VEE antigen in the IgG ELISA. Sensitivity of the IgG ELISA was determined by testing 100 coded pre- and postvaccination human sera. Sixty-two were positive by ELISA; 58 of these 62 were also positive by neutralization tests, and 38 were negative by both tests. No neutralization-positive, ELISA-negative sera were found. Comparison of titers obtained by ELISA and neutralization tests indicated that 88% varied randomly by a fourfold dilution factor or less, while 61% were identical or varied only twofold. In sera obtained sequentially from 10 vaccinees and 5 naturally infected patients, both IgG and IgM antibodies appeared between 2 and 3 weeks after vaccination or onset of symptoms. The IgG and IgM antibody ELISAs described are rapid, specific, and sensitive indicators of VEE antibody status in vaccinated and naturally infected individuals.

Adult↗
PubMed1982

Retention of fluorescent antigenicity of virus-infected cells on spotslides under various conditions of storage.

Ten well, epoxy-coated spotslides containing arbo- and arenavirus-infected cells were tested as determined by fluorescent methods for the retention of antigenicity after storage in a nitrogen atmosphere at various temperatures and times. In most cases antigen stability was maintained at -70 or -20 degrees C for periods exceeding 1-3 years. Antigen deterioration was greatest at ambient temperature, and less so at 4 degrees C.

Antigens, Viral↗
PubMed1981

Virion polypeptide heterogeneity among virulent and avirulent strains of eastern equine encephalitis (EEE) virus.

Comparative analysis of structural virion polypeptides of 24 selected EEE virus strains, representing North and South American types, was performed by one-dimensional discontinuous sodium dodecyl sulfate (SDS)-polyacrylamide-gel electrophoresis (PAGE). The structural proteins of different EEE virus isolates, resolved by this method, exhibited mol.wts. values in the range of 57-60 X 10(3) for (E-1), 51-54 X 10(3) for (E-2) and 35-38 X 10(3) daltons for the core (NP) nucleocapsid. The exception was the South American human lethal virus, TRVL-89287 strain, which was shown to possess only a single envelope glycoprotein. The high molecular weight envelope (E-1) glycoprotein species was absent or co-migrated adjacent to the smaller envelope (E-2) glycoprotein. Results indicated similarities in the core (NP) proteins, however greater variability in the envelope (E-/ and/or E-2) glycoproteins. Based on these variations seven distinct profiles could be observed among the EEE virus strain studied. The classification based on the patterns of structural polypeptides obtained by SDS-PAGE of these strains does not correlate well with any other previously reported in vitro characteristics (antigenic subtypes, HTP elution profiles) nor with the in vivo virulence markers.

Alphavirus↗
PubMed1981

Structural polypeptides of Hazara virus.

Four structural polypeptides of Hazara virus, an agent closely related to the Crimean-Congo haemorrhagic fever (C-CHF) viruses, were resolved by SDS-polyacrylamide gel electrophoresis. Three glycoproteins were identified (mol. wt. 84,000, 45,000 and 30,000) and were found to be associated with the virion envelope. A fourth polypeptide (mol. wt. 52,000) was non-glycosylated and associated with the nucleocapsid. The structural proteins of Hazara virus differ markedly from those reported for other bunyaviruses.

Bunyaviridae↗
PubMed1978

Virulence alterations of tacaribe virus infection in adult mice: lethal model for encephalitis.

Selection of population of Tacaribe virus strain 11573 lethal for mice was carried out by serial intracerebral passage of the virus in adult mice. Viral populations have been characterized by determination of virulence for suckling, weanling, and adult mice, and by histopathologic changes observed in brains of adult mice after intracerebral inoculation. Some of the virus preparations produced 80 to 90 per cent mortality after two or three intracerebral passages in adult mice and maintained this virulence for 1 to 3 passages, after which the virulence rapidly declined with subsequent passages. Clinical signs of infection in adult mice were manifested by a rough hair-coat, ventriflexed posture, diminished activity, increased excitability, flaccid hind-limb extension with progressive paralysis and death. Histologic examination revealed meningoencephalitis.

Age Factors↗
PubMed1978

Structural polypeptides of Machupo virus.

The structural proteins of an arenavirus pathogen, Machupo virus, were compared to the structural proteins of two previously characterized non-pathogenic arenaviruses, Pichinde and Tacaribe, in SDS-polyacrylamide gels. Similarities in mol. wt. of the major structural proteins from both pathogenic and non-pathogenic viruses were apparent; however, some differences in the number of glycosylation properties of minor proteins were observed. Machupo virions contain two major protein species. The most prominent is a non-glycosylated protein with a mol. wt. of 68000, while the other was glycosylated protein with a mol. wt. of 41000. Minor amounts of other proteins (mol. wt. 84000, 74000, 50000 and 15000) and a glycolipid were also observed.

Arenaviridae↗
PubMed1974

Structural components of Oriboca virus.

Analysis of purified Oriboca virions by neutral, sodium dodecyl sulfate polyacrylamide-gel electrophoresis indicated the presence of three structural polypeptides designated V-1, V-2, and V-3 on the basis of their relative electrophoretic mobilities in 8% gels. Polypeptides V-2 and V-3 are glycopeptides associated with the virion envelope as demonstrated by the preferential incorporation of labeled glucosamine into the polypeptides and by release of the polypeptides from the intact virion by the nonionic detergent NP-40. Polypeptide V-1 is the protein component of the nucleoprotein core of Oriboca virus as evidenced by the specific incorporation of uridine into the nucleoprotein, its release from the intact virion by NP-40 treatment, and its separation by both rate-zonal and isopycnic density gradient centrifugation from both the intact virion and envelope components. Molecular weights have been tentatively assigned to the polypeptides by extrapolation from the structural polypeptides of Sindbis virus when both are run in the same gel. Polypeptide V-1 has an apparent molecular weight of 20,000 to 23,000; V-2, 30,000 to 32,000; and V-3, 83,000 to 85,000.

Arboviruses↗