Biomedical subjects
Publications and source records attributed to G Morace.
The killer effect of 36 Hansenula, Pichia, Saccharomyces, and Candida species on 26 hyphomycetes isolates, 1 isolate of the achlorophyllous microorganism Prototheca, 4 isolates of the lipophilic yeast Malassezia, 1 isolate of the aerobic actinomycete Nocardia, and 19 isolates of bacteria was studied. The killer phenomenon, which was previously considered to be restricted to yeasts, was found to occur among unrelated microorganisms.
We studied reactive hyperemia in a group of patients with heart failure before and after therapy, since changes in the characteristics of muscular blood flow may influence the functional class of these patients. At the same time we evaluated some echocardiographic parameters too. When the patients improved clinically, they showed an increase in muscular blood flow at rest and in percent of fractional shortening and a decrease in peripheral vascular resistance. The reactive hyperemia did not change significantly. This fact probably depends on a maximal response to the postischemic hyperemia and represents the integrity of autoregulatory mechanisms.
The authors investigated the antigenic properties of a group of closely related dermatophytes whose components may be morphologically confused with one another: Microsporum canis, M. distortum, M. equinum, M. ferrugineum and Trichophyton soudanense. By using reference antigens and adsorbed monospecific antisera, it was possible to serologically distinguish the reference strains by the exoantigen technique. Their common and specific antigenic determinants were visualized by cross-immunoelectrophoresis tests with intermediate gel.
Killer toxins were isolated from eight selected killer yeasts. Their activity on 100 Candida albicans isolates of human and animal origin was studied. A computer aided system for differentiating C. albicans strains was developed. By using this system, it was possible to differentiate 14 biotypes of C. albicans isolates based on their susceptibility to the killer toxins.
A simple method for detecting hepatitis B virus DNA (HBV DNA) in serum using a filtration step for spotting sera on nitrocellulose paper followed by molecular hybridization is described. This method is rapid, sensitive, requires very small quantities of serum, and can be used for simultaneous testing of up to 96 samples in one filter apparatus. The sera tested for HBV DNA were also assayed for serological markers of HBV infection and comparison of data shows that on average 67% (30 of 45) of HBsAg- and HbeAg-positive sera contain HBV DNA, whereas 13% of HBsAg- and anti-HBe-positive sera contain HBV DNA. In general, there was a statistically significant correlation between the concentration of HBsAg in the serum and the presence or absence of HBV DNA. These results indicate that molecular hybridization is a valuable assay in addition to serological markers for identifying the possible infectivity of sera, and the simple and rapid method reported here makes the use of such hybridization technique easier.
Hybridoma cells produced by fusing myeloma cells with spleen cells from mice immunized with a soluble antigen of Microsporum canis yielded 30 antibody-producing clones. Six of these clones, propagated as ascites tumors in mice, showed two different types of monoclonal antibodies. The type 1 monoclonal antibody reacted with 17 heterologous and 10 homologous dermatophyte antigens. Type 2 monoclonal antibodies were unable to precipitate three antigens from different isolates of M. canis, thus suggesting the occurrence of different serotypes within the species.
The effects of isoproterenal (ISP) and methoxamine (MTX) infusion in 20 asymptomatic subjects with labile T wave were studied. In those treated with ISP the T wave showed an early negative trend and later became clearly positive in 5 subjects. In the majority of the subjects treated with MTX the T wave became positive. T wave changes match variations of both the ventricular gradient and, to a lesser degree, the QRS area. These changes were not related to heart rate or, in the subjects treated with MTX, to the baroreceptorial sensitivity deduced from the slope of the regression equation between R-R internal and systolic arterial pressure. The results of this study confirm the existence of a neurogenic mechanism affecting the electrocardiographic changes in T wave.
The authors perfected, for standardization purposes, a microautomated system (Dynatech MIC 2000 Inoculator) to obtain the accurate quantitative results, i.e., determination of minimum inhibitory (MIC) and fungicidal (MFC) concentrations, avoiding the work and time consuming procedure of the classic broth dilution method in tubes. The spectrum of activity of seven antifungal antibiotics against 204 yeast isolates of six different species, in two different media comparatively, is described.
High sensitivity rates to the activity of killer toxins produced by 25 species of yeasts belonging to the genera Candida, Hansenula, Pichia, Rhodotorula, Saccharomyces and Trichosporon have been observed among 112 yeast isolates (25 Cryptococcus neoformans, 29 C. glabrata 16 C. parapsilosis, 20 C. pseudotropicalis and 22 C. tropicalis). The highest sensitivity has been observed among the C. parapsilosis isolates, the lowest in C. glabrata strains. Genera Pichia and Hansenula proved to have the greatest killer activity. A killer system, formerly used for differentiating C. albicans isolates within the species, proved to be valid as epidemiological marker when applied to 112 strains of pathogenic yeasts.
Ten cluster headache patients and 10 healthy controls were subjected to electrocardiographic and pupillometric procedures in a search for cardiac and pupillary sympathergic asymmetry. Sympathergic stimulation was provoked by hyperventilation and by instilling tyramine into both eyes. In the control group, hyperventilation changed neither the T-wave form and polarity nor the QTc. Tyramine provoked an equal mydriasis on the two sides. In cluster headache sufferers, hyperventilation produced changes in the T-wave form and polarity as well as an increase of the QTc due to a disproportionate shortening of the R-R and Q-T intervals. An unequal mydriasis was noted after tyramine instillation due to less marked response on the symptomatic side. The observed electrocardiographic abnormalities are considered an expression of an asynchronous repolarization attributed to a sympathergic asymmetry. It is postulated that both the cardiac and pupillary sympathetic imbalance associated with cluster headache are central in origin.
Antibodies of IgG and IgM classes to Herpes simplex virus type 1 were detected, using the ELISA technique, in the cerebro-spinal fluid (CSF) and in the serum of four patients with encephalitis. All CSF and sera were positive for IgG antibodies; two CSF samples, which were collected quite early, were also positive for antibodies of IgM classes.
Immune-adherence haemagglutination (IAHA); single radial haemolysis and enzyme immunoassay (ELISA) versus haemagglutination inhibition (HAI) for detecting antibodies to measles virus were evaluated. The rank correlation computed according to Spearman for the sera of healthy individuals gave values of 0.66, 0.73, 0.72, respectively, for HAI-IAHA, HAI-single radial haemolysis (SRH) and HAI-ELISA. High percentages of accordance were observed as regards sera from both healthy and vaccinated individuals. In the case of vaccinated individuals the discordance analysis showed significant differences between HAI and IAHA, HAI and SRH, SRH and ELISA. The discordances indicate higher sensitivity of HAI and ELISA for the detection of seroconversion.
The killer effect of 37 species of Candida, Cryptococcus, Hansenula, Pichia, Rhodotorula, Saccharomyces, and Trichosporon on 100 Candida albicans isolates of human and animal origin was studied. All of the C. albicans cultures were sensitive to one or more killer yeasts. The factors affecting the killer phenomenon on C. albicans were investigated for realizing a simple system for the differentiation of the 100 C. albicans isolates. By using this system, it was possible to differentiate up to 512 isolates of C. albicans according to their susceptibility to the killer effect of nine selected killer yeasts. The use of this method as an epidemiological marker in the case of presumptive nosocomial infections due to C. albicans is also reported.
The Immunoenzymatic ELISA method has been applied to the detection of antibody to measles virus by using a single serum dilution. The reproducibility has been tested over three groups of sera negative, intermediate and strongly positive, in 48 different assays. The standard deviations and the variation coefficients are reported which show very good reproducibility both within and between runs. As regard sensitivity ELISA has proved more sensitive than Haemagglutination Inhibition (HAI) by testing sera both from healthy and vaccinated individuals. Variation of the absolute O.D. values has been found by using two different lots of plates. The use of control sera with various titres is recommended, and a reference scale may be valuable for normalization of the results.
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Preliminary results on the carcinogenic activity of a mycotoxin of Penicillium roqueforti (PR toxin) are reported. A squamous epithelioma and a uterine sarcoma were histologically confirmed in 2 of 10 albino rats fed PR toxin in a relatively short time (449 and 551 days respectively). Only an adenocarcinoma was histologically proven within a control group of 10 rats in a significantly longer (931 days) time span.
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