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Biomedical subjects

A Moroni

Publications and source records attributed to A Moroni.

At least 91 records · Page 5Linked to original sources
PubMed1992

Bioceramics in orthopaedic surgery: state of the art and preliminary results.

Ceramic materials utilized in orthopaedic surgery can be divided into bioinert, causing minimum tissue reaction, and bioactive types, capable of stimulating bone tissue growth, establishing a bond capable of supporting physiological loads. Alumina is a bioinert ceramic which shows excellent mechanical resistance and an extremely low level of wear when given appropriate structural characteristics. It is therefore used to make prosthetic hip components (head and acetabulum), to coat metal prosthetic shafts and to make prostheses for small joints. Among the bioactive ceramics, bioglass, bioglaze and hydroxylapatite are included in the study. At present, bioglass and bioglaze appear interesting, but not sufficiently so as to find a precise niche in orthopaedic surgery. Currently the bioactive ceramic with the most possibilities for use in orthopaedic surgery is hydroxylapatite. The close interfacial bond which is established with bone tissue allows it to be used as a filler for defective bones in various skeletal diseases and as a coating for metal prosthetic substrates.

Aluminum Oxide↗
PubMed1992

Proximal osteotomy of the tibia for the treatment of genu recurvatum in adults.

Twenty-seven opening-wedge osteotomies of the proximal part of the tibia were performed in twenty-five patients who had genu recurvatum. In sixteen knees, the genu recurvatum was due entirely to osseous deformity. In the remaining eleven knees, it was due to a combination of osseous and soft-tissue deformity; in five, the deformity was predominantly osseous and in six, primarily in the soft tissues (the ligaments and capsule). The average age of the patients was twenty-three years (range, fifteen to fifty-four years). The osteotomy was proximal to the tibial tuberosity in twenty-two knees. In eighteen of these knees, the tuberosity was detached with its patellar ligament and then reattached to the proximal part of the tibia over the block of bone in the opened wedge; in the remaining four knees, the tibial tuberosity was not detached. The osteotomy was distal to the tuberosity in five knees. The patients were followed for an average of 14.5 years (range, three to thirty years). Of the eighteen knees in which the osteotomy had been proximal to the tibial tuberosity and the tuberosity had been detached and then reattached, nine (50 per cent) had a result that was excellent; five (28 per cent), good; and four (22 per cent), fair. Of the four knees in which the operation had been proximal to but without detachment of the tuberosity, one had a result that was excellent; two, good; and one, fair. Of the five knees in which the osteotomy was distal to the tibial tuberosity, one had a result that was good; three, fair; and one, poor. Of the twenty-one knees in which the deformity was entirely or predominantly osseous, eighteen (86 per cent) had an excellent or good result. None of the six knees in which the deformity was predominantly in the soft tissues had an excellent or good result. Patients in whom the deformity was not primarily osseous, and those in whom the operation was distal to the tibial tubercle, were much more likely to have a fair or poor result.

Adolescent↗
PubMed1992

Differential cleavage of surface proteins of Borrelia burgdorferi by proteases.

The differential cleavage of surface proteins of Borrelia burgdorferi IRS strains by several proteases was examined. Proteinase K, trypsin, chymotrypsin and thermolysin all cleaved the outer surface protein B (OspB) to undetectable levels by Coomassie Brilliant Blue staining, whereas some residual protein was detected by immunoblotting with polyclonal and monoclonal antibodies. Not even antigenic fragments were detectable by immunoblotting with 1A8 monoclonal antibody reactive with OspB. Less effective or ineffective was the cleavage of OspB by V8 protease and proteinase A, respectively. The outer surface protein A was cleaved only by proteinase K. The effect of trypsin on borreliae viability and adhesion to cultured cells was also studied. The trypsin treatment of borreliae did not impair the viability of organisms which continued to synthesize the cleaved OspB. The attachment of B. burgdorferi to HEp-2 cells was reduced by 41% after treatment with trypsin, whereas preincubation of borreliae with monoclonal antibody 1A8 and guinea pig immune serum reduced the adhesion of borreliae to the cells by 32% and 87%, respectively.

Antibodies, Monoclonal↗
PubMed1991

Cryptochrome, phytochrome, and anthocyanin production.

Anthocyanin production in cabbage (Brassica oleracea L.) and tomato (Lycopersicon esculentum Mill.) seedlings exposed to prolonged irradiations was studied under conditions that allowed discrimination, within certain limits, between the contribution of cryptochrome and phytochrome in the photoregulation of the response. The results of the study provide confirming evidence for the involvement of cryptochrome and direct evidence for a significant contribution of cryptochrome to the fluence rate dependence of the response to blue. The results provide some preliminary, direct indication for an interaction between cryptochrome and phytochrome in the photoregulation of anthocyanin production in seedlings exposed to the prolonged irradiations required for a high level of expression of the response. The type and degree of interaction between the two photoreceptors vary significantly, depending on the species and experimental conditions.

Journal Article↗
PubMed1991

Immunological characterization of a low molecular mass polypeptidic antigen of Borrelia burgdorferi.

The presence of a low molecular mass polypeptidic antigen in Borrelia burgdorferi was described. The protein was exposed at the bacterial surface since it was clearly identified by mAb 3H4 using the immunofluorescence test performed with living bacteria. This antigen was cleaved by proteinase K treatment, whereas it was resistant to the action of chymotrypsin, trypsin and thermolysin. Western blotting analysis of the immunological reactivity of this antigenic structure performed using monoclonal antibody, mouse-immune ascitic fluids raised against B. burgdorferi and other spirochetes, sera from patients with Lyme disease and other infirmities in which false positive results in serological tests for B. burgdorferi have been described, demonstrated that this protein expresses only species-specific epitopes which may be recognized during human B. burgdorferi infections.

Animals↗
PubMed1991

Detection of Chlamydia trachomatis DNA in patients with non-gonococcal urethritis using the polymerase chain reaction.

A practical protocol using the polymerase chain reaction (PCR) was designed for detecting Chlamydia trachomatis in clinical samples. DNA was extracted from material collected on urethral swabs and used as substrate for the PCR. The target was a 600 basepair DNA segment of the multicopy plasmid that is common to all strains of the bacterium. Negative samples were checked for loss of DNA or presence of polymerase inhibitors by a second PCR, targeted to a conserved segment of the human genome. The whole procedure was tested on 216 men with non-gonococcal urethritis (NGU). All patients were independently assessed by tissue culture isolation (60 positive samples) and a commercial immunoenzymatic assay. The PCR protocol, while sufficiently simple for routine application, was reliable and, for the diagnosis of urethritis, at least as good as tissue culture isolation.

Adolescent↗
PubMed1991

In-vitro activity of roxithromycin against Chlamydia trachomatis.

Ten Chlamydia trachomatis isolates were tested for their sensitivity to roxithromycin, in comparison with erythromycin and tetracycline. The minimum inhibitory and minimum bactericidal concentrations of roxithromycin ranged from 0.03-0.12 and 0.25-1 microg/ml, respectively.

Anti-Bacterial Agents↗
PubMed1991

Influence of the fluoride ion in the stability of bone hydroxyapatite achieved in patients after the fluo-calcic therapy.

It has been proposed that fluoride ion might actively enter into the basic structural framework of the bone, within its main constituent, the hydroxyapatite (HA), by substituting systematically the OH- ion in the crystal chemical formula Ca5[(PO4)3OH]. Accurate compositional studies have become necessary in order to explain an eventual stabilizing effect. Loss in weight (TG) and chemical reaction (DTG) while varying the temperature have been carried out for the first time on specimens under normal conditions and after fluo-calcic treatment, in parallel with accurate chemical compositional determinations by atomic absorption analysis. Our investigation shows that the new structure present after treatment is mechanically stable and proves more resistant to osteolytic processes.

Bone Neoplasms↗
PubMed1990

Friedreich's ataxia: a descriptive epidemiological study in an Italian population.

All the cases of Friedreich's ataxia (FA) diagnosed between 1945 through 1984 among residents of a defined area of northwestern Italy were ascertained (N = 59). Cases were diagnosed according to the criteria of the "Quebec Cooperative Study on Friedreich's Ataxia (QCSFA)" with minor modifications. We identified 39 families with 47 probands and 12 secondary cases. Therefore ascertainment probability was 80%. Male to female ratio was 1:1. Pedigrees were compatible with autosomal recessive inheritance. Segregation ratio was 0.28 with both Weinberg's method and the "singles" method (under incomplete ascertainment). Point prevalence ratio was 1.2/100,000 population. Birth incidence rate was 1/36,000 live births. Gene frequency was estimated to be 1/191. The ratio of first-cousin marriages observed among parents of FA patients (3%) was lower than expected from Dahlberg's formula (8%). This finding is not compatible with the hypothesis of genetic heterogeneity for FA.

Adolescent↗
PubMed1990

Bone mineral alterations and Mg content in aging.

The authors propose to determine whether the quantity of bone mass reduction linked to aging is accompanied by qualitative modifications of the mineral structure. To this end, 18 samples of cancellous bone from the femoral heads of two groups of patients (Groups A & B), were examined. Group A was made up of 8 old osteopenic patients suffering from fracture of the femur neck (age 62-84). Group B consisted of 10 young non-osteopenic subjects (age 34-53). Through chemical analysis a statistically significant percentage increase in Mg++ was noted in Group A and, by X-Ray diffraction, significant presence of beta-TCP. Mineral structure alterations occur in the process of aging of the skeletal tissue.

Adult↗
PubMed1989

Serological response to chlamydial infection in sheep, studied by enzyme-linked immunosorbent assay and immunoblotting.

Two enzyme-linked immunosorbent assays (ELISA) using highly purified elementary bodies (EB) of Chlamydia psittaci A/22 strain (ovine) or 6BC strain (psittacine) were set up for the detection of antichlamydial antibodies in sheep. No significant differences were observed between the two ELISAs, whereas these tests proved to be more sensitive than complement fixation test and showed a good correlation (r = 0.75) with immunofluorescence assay. The periodate treatment of chlamydial antigens modified the results of serological responses studied by ELISA, depending on the sera. The average reduction of ELISA values by periodate was 28%, ranging between 5% and 65%. The immunoblot analysis of sheep sera showed high cross reactivity between the polypeptides of A/22 and 6BC strains. However, some differences were observed. The major outer membrane protein (MOMP) of 6BC strain was recognized at different molecular weight position (40,000 kDa) in comparison with the MOMP of A/22 strain (38,000 kDa). In addition, a clear band of 97,000 kDa was detected by all sheep sera tested with A/22 strain. This band was undetectable in the blots performed with 6BC strain.

Animals↗
PubMed1988

Mineralization and calcium fixation within a porous apatitic ceramic material after implantation in the femur of rabbits.

Cylinders (0.8 cm long, 1.0 cm of diameter and with an axial hole), constituted, after firing, of a ceramic mixture of hydroxylapatite (HA) and beta-tricalciumphosphate (beta-TCP) in a 10:1 ratio, were implanted into mid-diaphyseal defects of one femur of 20 rabbits and stabilized with intramedullary rods. The implantation sites were checked radiographically every month, and after 3 months (3 animals) and 6 months (17 animals) the rabbits were sacrificed and the implants with the surrounding tissue were embedded in methylmethacrylate, cut to thick sections and analyzed by scanning electron microscopy (SEM). Porosimetric and x-rays diffraction analyses were carried out before and after implantation of the cylinders, and the state of mineralization at the bone-implant interface was determined by EDAX microprobe analysis. Bony callus formation started at 1 month at the osteotomy sites, as judged by radiography, but after 3 months a not-mineralized zone had still been demonstrated between bone and the implants. At 6 months, 13 implants showed themselves firmly fixed in their implantations beds, while 4 implants were only incorporated at their proximal ends. In bone contact zones, an enrichment of Ca2+ was displayed by microanalytical techniques in the outer zone of the implanted samples which may be explained by an apparent additional phase transformation of HA into TCP, thanks to the change of the Ca/P ratio, that takes place in vivo.

Animals↗
PubMed1988

Specific Epstein-Barr virus serological response in patients with nasopharyngeal carcinoma detected by immunoblotting.

The specific humoral immune response against Epstein-Barr virus (EBV) antigens in patients with nasopharyngeal carcinoma (NPC) was compared to that of patients with infectious mononucleosis (IM) and other EBV-seropositive subjects using immunoblotting technique. Almost all sera from EBV serologically associated NPC reacted reproducibly with a major group of polypeptides (four to six) of early antigen (EA) complex with molecular weights ranging from 50 kD to 58 kD, and with some additional polypeptides. Sera from IM-patients reproducibly recognized only one polypeptide of 50 kD belonging to the major group of polypeptides of EA-complex. Sera from patients with other types of head and neck cancer and relatively high levels of IgG antibody against viral capsid antigen (VCA) and EA did not react reproducibly with any of the EBV-associated proteins.

Carcinoma↗
PubMed1988

Structural modifications and biological compatibility of doped bio-active glasses.

The Raman laser and infrared spectra of doped bio-active glasses of the 45S5 type are presented and discussed. The spectroscopic results show that the doping agents cause the destruction of the basic glass structure and the consequent formation of SiO4(4-) units in the glass network. When the doped glasses have been immersed in a physiological solution (199 medium), a film of calcite forms on the glass surface and this modification is related to the type of doping agent used, decisive for close linking between metal supports and the glass. The presence of doping agents does not prevent the normal growth of the bone onto the surface of doped bioactive glasses. Histological tests show that tissue response to very fine powders of doped glasses increases up to 15 days more or less according to the structural modifications revealed by spectroscopic measurements.

Animals↗
PubMed1988

Plasmalemma redox activity and h extrusion: I. Activation of the h-pump by ferricyanide-induced potential depolarization and cytoplasm acidification.

Ferricyanide reduction by Elodea densa leaves, in the dark, is associated with: (a) acidification of the medium; (b) decrease (about 0.2-0.3 units) of intracellular pH (measured in cell sap, cytoplasm, and vacuole); (c) depolarization of the transmembrane potential; (d) net efflux of K(+) to the medium. Ferricyanide-induced acid secretion is markedly increased by the presence of fusicoccin (FC), and this effect is severely inhibited by the proton pump inhibitors erythrosine B and vanadate. In the presence of ferricyanide FC-induced H(+) extrusion no longer requires the presence of K(+) in the medium. The (ferricyanide reduced)/(H(+) extruded) ratio varies from about 2, in the absence of FC, to about 1 when the toxin is present, and to more than 4, when ATP-driven H(+) extrusion is inhibited by erythrosine B or by vanadate. Fusicoccin markedly reduces K(+) release to the medium. The ratio (ferricyanide reduced)/(H(+) extruded + K(+) released) approaches unity under all of the three conditions considered. These results indicate that ferricyanide reduction depends on a plasmalemma system transporting only electrons to the extracellular acceptor, with consequent potential depolarization and cytoplasm acidification. Most of the protons released in the cytoplasm would be secondarily extruded by the ATP-driven pump, stimulated by both intracellular acidification and depolarization. K(+) efflux would depend on potential depolarization.

Journal Article↗
PubMed1988

Densitometric analysis in in vivo evaluation of synthetic salmon calcitonin activity.

In women suffering from post-menopausal osteoporosis, we evaluated the effectiveness of two cyclic treatments with synthetic salmon calcitonin over a whole year, using an average daily dose of 16 and 32 IU, respectively. This treatment was compared with treatment with oral calcium carbonate. The results, evaluated by peripheral densitometry of the radius, showed a 3.2% loss of bone mineral content (BMC) in the women treated only with calcium carbonate, a loss of 1% in those treated with an average dose of 16 IU/day of calcitonin and an increase of 4% in the women treated with an average dose of 32 IU/day (an increase just above the statistically significant limit using the paired t-test). An average dose of 32 IU/day probably represents the minimum effective dose of calcitonin required to produce a significant increase in bone mineral mass, when used according to a sequential scheme.

Aged↗