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Biomedical subjects

M Gatti

Publications and source records attributed to M Gatti.

At least 109 records · Page 6Linked to original sources

Incidence of endogenous and exogenous opportunistic fungal infections in relation to different prophylactic measures: clinical and microbiological study of 431 immunocompromised patients.

Two groups of immunocompromised patients were studied with the aim of pointing out the possibilities of antifungal prophylaxis in this type of patient. All patients received oral treatment with nystatin, but only the patients of one group were also in strict reverse isolation. It has been confirmed that chemoprophylactic treatments may control opportunistic endogenous mycoses effectually. On the contrary, only reverse isolation seems to be effective against airborne exogenous fungal infections. Because of the difficulty and high cost of this practice, different modalities for a really generalizable antifungal prophylaxis are required. At present only the detection of new systemic antifungal drugs, which are not toxic and are easy to use, seems hopeful.

Fungi↗

Intensive care units as a source of methicillin-resistant Staphylococcus aureus.

Over a 12 month period, 209 isolates of methicillin resistant Staphylococcus aureus (MRSA) were obtained in 39 patients admitted to an ICU. In 23 patients MRSA was the major pathogen, producing either pneumonia, bacteremia or wound infection. In eight patients death was directly related to the MRSA infection. This study suggests an increasing occurrence of MRSA infections in ICU and the need to adopt control measures.

Adolescent↗

Colour blindness distribution in the male population of Rome.

A total of 3,285 young males selected at random from the school population of Rome have been administered the Ishihara plates for colour blindness. Those who failed to read all plates correctly were further administered Farnsworth's Panel D-15 and the diagnoses of colour blindness were made by an ophthalmologist and cross checked. A total of 201 subjects were found to be colour-blind, allowing a gene frequency estimate of 0.061 +/- 0.004. This is the first reliable estimate for the Italian population and appears to be lower than for other Caucasoid populations. The gene frequency of colour blindness is known to increase from 0.02-0.04 in 'primitive' populations to 0.07-0.09 in Caucasoid populations, possibly as a result of a selection relaxation.

Adolescent↗

Mutations in genes encoding essential mitotic functions in Drosophila melanogaster.

Temperature-sensitive mutations at 15 loci that affect the fidelity of mitotic chromosome behavior have been isolated in Drosophila melanogaster. These mitotic mutants were detected in a collection of 168 EMS-induced X-linked temperature-sensitive (ts) lethal and semilethal mutants. Our screen for mutations with mitotic effects was based upon the reasoning that under semirestrictive conditions such mutations could cause an elevated frequency of mitotic chromosome misbehavior and that such events would be detectable with somatic cell genetic techniques. Males hemizygous for each ts lethal and heterozygous for the recessive autosomal cell marker mwh were reared under semirestrictive conditions, and the wings of those individuals surviving to adulthood were examined for an increased frequency of mwh clones. Those mutations producing elevated levels of chromosome instability during growth of the wing imaginal disc were also examined for their effects on chromosome behavior in the cell lineages producing the abdominal cuticle. Fifteen mutations affect chromosome behavior in both wing and abdominal cells and thus identify loci generally required for the fidelity of mitotic chromosome transmission. Mapping and complementation tests show that these mutations represent 15 loci. One mutant is an allele of a locus (mus-101) previously identified by mutagen-sensitive mutants and a second mutant is an allele of the lethal locus zw 10.--The 15 mutants were also examined cytologically for their effects on chromosomes in larval neuroblasts. Taken together, the results of our cytological and genetical studies show that these mutants identify loci with wild-type functions necessary for either maintenance of chromosome integrity or regular disjunction of chromosomes or chromosome condensation. Thus, these mutations define a broad spectrum of genes required for the normal execution of the mitotic chromosome cycle.

Alleles↗

A gene controlling condensation of heterochromatin in Drosophila melanogaster.

A temperature-sensitive lethal mutant of Drosophila melanogaster was used to identify an essential cell cycle function that is necessary for the mitotic condensation of heterochromatic but not of euchromatic portions of the genome. This mutant is an allele at a locus (mus-101) identified earlier by the use of mutagen-sensitive mutants. The data suggest that the mutagen-sensitive and repair-defective phenotypes of viable mus-101 mutants result from a disruption in chromosome organization.

Animals↗

[Evaluation of functional periodicity of the pituitary gland by harmonic analysis.--III Circadian prolactin secretion in subjects with prolactin-secreting adenoma].

The 24-hour periodicity of PRL secretion in 7 prolactinoma subjects of both sexes has been studied by means of the Fourier's harmonic analysis. In all cases elevated PRL titres have been found, that did not show the physiological changes due to sleep and wake. In most of the cases could not be demonstrated either a significant secretory periodicity or secretory episodes occurred with a frequency higher than in the control groups. Such secretory features may depend on changes in the neoplastic cells' receptors for regulating neurotransmitters.

Adenoma↗

Renal dysfunction as a possible cause of essential hypertension in predisposed subjects.

In 65 young normotensive subjects with two hypertensive parents (HP), and in 55 matched subjects with two normotensive parents (NP), the following factors were measured: renal plasma flow (RPF), glomerular filtration rate (GFR) both as Inutest and creatinine clearances; 24-hr urinary output; plasma renin activity (PRA); Na and K in plasma and in 24-hr urine and 24-hr urinary excretion of aldosterone. In 30 HP and in 34 NP, the cardiac output and plasma concentrations of noradrenaline, adrenaline, and dopamine were also measured in the supine position and after 10 min of standing. The HP have greater RPF (P less than 0.01), faster GFR (P less than 0.02), greater 24-hr urinary output (P less than 0.05), and lower PRA (P less than 0.01) than the NP. All the other factors were similar in the two groups of patients. It is proposed that the differences in renal function in the HP and the NP may be due to an abnormality in tubular handling of ions and water in the HP, which may be responsible for the increase in blood pressure in a proportion of patients with essential hypertension.

Adolescent↗

Region-specific effects on chromosome integrity of mutations at essential loci in Drosophila melanogaster.

Two mutagen-sensitive loci of Drosophila melanogaster, mus-105 and mus-109, previously identified by viable alleles, are shown to specify essential functions. Lethal alleles at the loci produce larvae that have degenerate imaginal discs and die at the larva-pupa boundary. Our data suggest that the causes of lethality are intolerable levels of cell death produced by high frequencies of chromosome aberrations (in excess of 0.5 aberration per cell per cycle). The pattern of aberrations is a locus-specific character. In mus-105 mutants the most common aberrations are breaks and exchanges in euchromatic portions of the genome whereas in mus-109 mutants the most common aberrations are breaks at heterochromatin-euchromatin junctions. The sensitivity of these junctions to breakage in mus-109 mutants is a property of all such junctions whether natural or produced by a rearrangement that juxtaposes heterochromatin and euchromatin. Larvae carrying the combination of two viable mutants, mus-105(A1) mus-109(D1), die at the larva-pupa boundary and display a high frequency of aberrations (0.7 per cell vs. 0.075 for either mutant alone) clustered at euchromatin-heterochromatin junctions. This synergistic interaction suggests there is a class of lesions that can be repaired by both mus-105(+) and mus-109(+). Thus, the apparent euchromatic specificity of mus-105(+), which was inferred from the pattern of predominantly euchromatic breakage observed in mus-105 mus-109(+) flies, is in fact generated by the wild-type function of mus-109(+) masking an effect of mus-105 in the heterochromatin. The fact that lethal mutants at the mus-105 and mus-109 loci have small imaginal discs coupled with the observation of a maternal effect of mus-105 suggests a paradigm for the control of cell division during the life cycle of Drosophila.

Alleles↗