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Biomedical subjects

S Resta

Publications and source records attributed to S Resta.

At least 19 recordsLinked to original sources
PubMed2005

Microspheres leaching for scaffold porosity control.

Scaffold morphology plays a key role in the development of tissue engineering constructs. The control of pore size, shape and interconnection is needed to achieve adequate nutrient transport and cell ingrowth. Several techniques are available for scaffold manufacturing, but none allows easy control of morphology and is, at the same time, applicable to a wide variety of materials. To investigate the possibility of processing a wide range polymers by solvent casting/particulate leaching with accurate control of scaffold morphology, three different porogens (gelatin microspheres, paraffin microspheres and sodium chloride crystals) were used to fabricate scaffolds from commonly employed biodegradable polymers. The outcome of processing was evaluated in terms of scaffold morphology and structure/properties relationships. Highly porous scaffolds were obtained with all porogens and well defined spherical pores resulted from microspheres leaching. Furthermore, scaffolds with spherical pores showed better mechanical performance and lower flow resistance. Cytocompatibility tests performed showed no evidence of processing residuals released from the scaffolds. Solvent casting/microspheres leaching, particularly gelatin microspheres leaching, can be used to process a large number of polymers and enables to tailor scaffold pore size, shape and interconnection, thus providing a powerful tool for material selection and optimization of scaffold morphology.

Microscopy, Electron, Scanning↗
PubMed1997

Clinical, histological, and virological features of hepatitis C virus carriers with persistently normal or abnormal alanine transaminase levels.

This study was aimed to evaluate demographic, clinical, histological, and virological characteristics of 46 hepatitis C virus (HCV) carriers with persistently normal alanine transaminase (ALT) levels and to compare the results with those obtained in a group of 52 HCV-RNA-positive patients with elevated ALT levels. Subjects with normal ALT were more often females (P < .001), were more likely to be asymptomatic (P < .001), and have a lower incidence of risk factors for HCV transmission (P < .01). All patients with normal ALT had significant histological liver damage. The mean grading and staging did not differ between patients with normal and those with raised ALT concentrations. Moderate to severe hepatitis was more frequently found among subjects with normal than with elevated ALT. HCV genotype 2a was far more common in subjects with normal (43%) than with abnormal ALT levels (6%; P < .002), genotype 1b being more frequent in these latter (50% vs. 17%; P < .001). Patients with normal ALT levels had similar serum HCV-RNA titers than subjects with raised ALT. Neither HCV genotype distribution nor viral load correlated with the severity of liver damage. We conclude that significant liver disease may occur irrespective of clinical symptoms, ALT levels, HCV genotypes, and viral load.

Adult↗
PubMed1992

A controlled trial of ganciclovir to prevent cytomegalovirus disease after heart transplantation.

BACKGROUND: Because of the immunosuppression required, heart-transplant recipients frequently have complications caused by cytomegalovirus (CMV), including pneumonia, esophagitis, gastritis, and a syndrome of fever, hepatitis, and leukopenia. We undertook a controlled trial to evaluate the prophylactic administration of ganciclovir to prevent CMV-induced disease after heart transplantation. METHODS: This randomized, double-blind, placebo-controlled trial was conducted at four centers. Before randomization, the patients were stratified into two groups: those who were seropositive for CMV before transplantation and those who were seronegative but who received hearts from seropositive donors. Ganciclovir was given intravenously at a dose of 5 mg per kilogram of body weight every 12 hours from postoperative day 1 through day 14, then at a dose of 6 mg per kilogram each day for 5 days per week until day 28. RESULTS: Among the seropositive patients, CMV illness occurred during the first 120 days after heart transplantation in 26 of 56 patients given placebo (46 percent), as compared with 5 of 56 patients treated with ganciclovir (9 percent) (P less than 0.001). Among 37 seronegative patients, CMV illness was frequent in both groups (placebo, 29 percent; ganciclovir, 35 percent; P not significant). From day 15 through day 60, the patients who took ganciclovir had significantly fewer urine cultures positive for CMV, but by day 90 there was no difference. More of the ganciclovir-treated patients had serum creatinine concentrations greater than or equal to 221 mumol per liter (2.5 mg per deciliter) (18 percent vs. 4 percent in the placebo group), but those elevations were transient. CONCLUSIONS: The prophylactic administration of ganciclovir after heart transplantation is safe, and in CMV-seropositive patients it reduces the incidence of CMV-induced illness.

Adolescent↗
PubMed1991

Human cytomegalovirus glycoprotein-receptor interactions.

The HCMV envelope glycoprotein having a molecular weight of 86 kd, gH, has been shown to react with a 92 kd protein that can be extracted from HEL fibroblasts. This HCMV-gp86 membrane receptor appears to be present on the surface of both HCMV-permissive and HCMV-non-permissive cells, suggesting that there are factors in addition to viral attachment governing the intracellular replicative process. Another HCMV envelope glycoprotein (gp130/55; gB homologue) binds predominantly to a 31 kd protein with minor bands at 180, 96, and 90 kd. HCMV-gp86 does not bind to the principal gp130/55 receptor.

Antibodies, Monoclonal↗
PubMed1985

Isolation and propagation of a human enteric coronavirus.

Coronavirus-like particles were found by electron microscopy in stools from infants with necrotizing enterocolitis. Stool samples from these infants as well as control specimens were passaged in cultures of human fetal intestinal organs. Two samples yielded virus-like particles and these have now been passaged 14 times (HEC 14). Gradient-purified HEC 14 strains had typical coronavirus morphology on electron microscopy and contained five major proteins with molecular sizes ranging from 190 to 23 kilodaltons. Infants with necrotizing enterocolitis developed specific antibody to the viral antigens between the acute and convalescent stages of the disease, as shown by examining serum specimens by single radial hemolysis, immunoenzymatic assay, and Western immunoblotting. No cross-reactivity was shown with other coronavirus strains tested, or with the newly isolated viruses of the Breda-Berne group, responsible for calf or horse diarrhea.

Antigens, Viral↗
PubMed1982

[Antibody response to trivalent anti-influenza vaccination (inactivated virus) A/Texas/1/77 H3N2), A/URSS/90/77 (H1N1), B/Hong Kong/8/73].

Seventy-five young recruits received an intramuscular dose of anti-influenza virus vaccine containing 300 U.I. of A/Texas/1/77 (H3N2), A/URSS/90/77 (H1N1), B/Hong Kong/8/73 strains. Antibody responses were detected by HI and SRH tests: immunogenicity of the preparation was different for the individual vaccine strain in spite of the similar amount of antigenic content, and the immunity conferred by vaccine strains did not significantly extend to new influenza virus strains which prevailed in 1979/80 winter season with the exception for A/Brazil/11/78 (H1N1).

Adult↗
PubMed1980

[Seroepidemiology of rubella in Rome (1972-1978)].

Data on hemoagglutination inhibition (HI) tests for rubella immunity which were performed in our laboratory since 1972, are reported. The results obtained on sera from healthy young women indicate a significant decrease of incidence of sero-negatives in 1978 as compared with previous years. The incidence of high titer-positive sera and the geometric mean titer of HI antibody were significantly greater in 1973 and 1978 than in the remaining years; a greater number of case reports to Public Health Authorities occurred in Rome during these two years. The data are also discussed in relationship with vaccination program.

Antibodies, Viral↗
PubMed1980

Antibody reactive in antibody-dependent cell-mediated cytotoxicity following influenza virus vaccination.

The antibody reactive in antibody-dependent, cell-mediated cytotoxicity (ADCC) to influenza virus-infected cells was measured in two groups of seven volunteers each, before and after immunization with inactivated or live attenuated A/Victoria/3/75 influenza virus vaccines. Age-matched controls were seven adult individuals who experienced natural influenza infection due to A/Victoria/3/75-like virus strain. After inactivated whole influenza virus immunization all the subjects showed a significant rise of the antibody reactive in ADCC (from a mean value of 4.7% to 17.1% cytotoxicity, before and 5 weeks after immunization, respectively) as well as of hemagglutination inhibition (HI) antibody (fourfold or greater increase). These immune responses were similar to those observed among naturally infected controls. After live attenuated virus vaccination, no significant increase in titer of antibody reactive in ADCC was detected, even though the vaccine induced significant increase of HI antibody titer. Little correlation was found between ADCC and HI antibody rises in sera of recipients of inactivated virus vaccine and of naturally infected individuals while, in live attenuated influenza virus vaccines, the rise of HI antibody titer did not correspond to a significant increase of ADCC antibody titer did not show subjects who developed a significant rise in ADCC antibody titer did not show significant variation in antibody to neuraminidase and/or to complement fixation influenza virus antigens.

Adolescent↗
PubMed1980

Secretory immune response after nasal vaccination with live attenuated influenza viruses.

Immunoglobulins and virus-specific antibody in nasal secretions were measured in 18 volunteers before and after intra-nasal vaccination with two live-attenuated type A influenza virus strains. Specific serum antibody rises occurred in 14 out of 18 vaccinees; of those, 11 and 10, respectively, showed significant increase of IgA concentration and of virus-specific antibody in nasal secretions collected 2-4 weeks after vaccination. In one case, a volunteer showed appreciable increase of virus neutralizing antibody in nasal secretions without increase of local IgA concentration and of serum HI antibody. This data indicate that administration of live virus vaccines by upper respiratory route confers effective immunity associated with local antibody synthesis.

Adult↗
PubMedDate not supplied

Cytomegalovirus: where have we been and where are we going?

Nearly 30 years have elapsed since Rowe and Weller and their colleagues discovered human cytomegalovirus (CMV). Because of its complex structure, long replicative cycle, low yield in vitro, and highly species-specific cell-substrate requirement, the cellular and molecular biologic analyses of human CMV have been slow, but recombinant DNA and monoclonal antibody technologies are bringing about rapid changes. Because of the long period of latency and wide range of disease presentations, epidemiologic and medical insights have also come slowly. However, the clinical events that occur during iatrogenic immunosuppression (transplantation and cancer therapy) and as a result of immunocompromise due to human immunodeficiency virus infection are currently promoting our understanding of the epidemiology of CMV disease and the definition of its clinical spectrum. Rapid diagnostic methods, antiviral drugs, and vaccines for CMV are becoming available. We may not yet understand completely the impact of this agent on the nonimmunosuppressed or aspects of its pathogenesis: e.g., the immune functions controlling recrudescence and the possibility of increased disease severity in those with no detectable immune defect. With the availability of new approaches, other issues should be clarified, such as the functions of host and virus involved in the mechanism of persistence.

Acquired Immunodeficiency Syndrome↗