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Biomedical subjects

A Lombardo

Publications and source records attributed to A Lombardo.

17 recordsLinked to original sources
PubMed1992

Abnormal intraventricular flow patterns in left ventricular dysfunction determined by color Doppler study.

We examined the relation between left ventricular (LV) flow dynamics measured by color Doppler, and either global or regional LV function in 19 normal subjects (group 1), in 55 patients with old myocardial infarction (MI) (29 without [group 2] and 26 with LV aneurysm [group 3]), and in 16 with idiopathic dilated cardiomyopathy (group 4). We calculated by M-mode color Doppler a flow persistence index (FPI) (duration of flow directed in systole toward the apex/LV ejection time). Contrast echocardiography was performed as a control method in 14 patients of the four groups. In normal subjects, rapid systolic inversion of flow toward the aorta was evident (FPI: 0.11 +/- 0.16). In all but one patient in group 2, a similar LV flow pattern was observed, but FPI was greater (0.32 +/- 0.26). In groups 3 and 4, a paradoxical antegrade LV flow pattern was evident during the entire period of systole (FPI: 1.13 +/- 0.42 and 1.28 +/- 0.36, respectively). LV flow patterns were reproduced in echo-contrast studies. FPI was related to LV end-diastolic volume (r = 0.77), end-systolic volume (r = 0.82), and ejection fraction (r = -0.84). However, when data were analyzed separately in the different groups, these correlations were significant only in groups 2 and 3. Paradoxical flow pattern is not peculiar to regional LV dysfunction; it also occurs in global LV dysfunction. This LV flow abnormality may develop after MI even in the absence of severe LV dyssynergy or dilation, and is quantitatively related to the degree of LV dysfunction.

Adult↗
PubMed1992

Control of mRNA turnover as a mechanism of glucose repression in Saccharomyces cerevisiae.

We have examined the expression of the gene encoding the iron-protein subunit (Ip) of succinate dehydrogenase in Saccharomyces cerevisiae. The gene had been cloned by us and shown to be subject to glucose regulation (A. Lombardo, K. Carine, and I. E. Scheffler, J. Biol. Chem. 265:10419-10423, 1990). We discovered that a significant part of the regulation of the Ip mRNA levels by glucose involves the regulation of the turnover rate of this mRNA. In the presence of glucose, the half-life appears to be less than 5 min, while in glycerol medium, the half-life is greater than 60 min. The gene is also regulated transcriptionally by glucose. The upstream promoter sequence appeared to have four regulatory elements with consensus sequences shown to be responsible for the interaction with the HAP2/3/4 regulatory complex. A deletion analysis has shown that the two distal elements are redundant. These measurements were carried out by Northern (RNA) analyses of Ip mRNA transcripts as well as by assays of beta-galactosidase activity in cells carrying constructs of the Ip promoter linked to the lacZ coding sequence. These observations on the regulation of mRNA stability were also extended to the mRNA of the flavoprotein subunit of succinate dehydrogenase and in some experiments of iso-1-cytochrome c.

Cloning, Molecular↗
PubMed1992

Acromegalic cardiomyopathy. Left ventricular filling and hypertrophy in active and surgically treated disease.

Myocardial hypertrophy and interstitial fibrosis are common in acromegalic hearts and may induce left ventricular (LV) dysfunction. The transmitral flow pattern was examined by pulsed-wave Doppler in 20 patients with active acromegaly and nine with acromegaly cured by pituitary microsurgery. Control groups consisted of 25 normal subjects and 13 patients with systemic hypertension. We related Doppler indices of LV filling (E and A peak velocities and E/A ratio) to the duration of acromegalic disease, the GH plasma levels and LV mass. The LV mass/BSA was significantly greater in active acromegaly (187 +/- 53 g/sq m) and systemic hypertension groups (161 +/- 48 g/sq m) than in cured acromegaly (125 +/- 35 g/sq m) and the normal control group (109 +/- 36 g/sq m) (p < 0.01 for both). No differences were found in the E peak velocity, A peak velocity, and E/A ratio in the groups with active acromegaly (E/A: 0.9 +/- 0.2), cured acromegaly (E/A: 0.9 +/- 0.3), and systemic hypertension (E/A: 0.8 +/- 0.5). An E/A ratio < 1 was found in 13 patients with active and four with cured acromegaly; (p = NS). In the active acromegaly group, the E/A ratio was related to either LV mass or the duration of disease (r:-0.45 and -0.47, respectively; p < 0.05). In the cured acromegaly group, the E/A ratio was related to the duration of disease before surgery (r:-0.70; p < 0.05) and not to LV mass (r:0.12). In conclusion, an impairment in LV filling may be present not only in the patients with active acromegaly but also in those successfully treated by surgery after a long duration of the disease, despite normal LV mass. These LV filling abnormalities may be in part determined by nonreversible myocardial changes, such as interstitial tissue fibrosis.

Acromegaly↗
PubMed1992

Preparation of a stable liquid material for calibration and quality control for lysosomal enzymes in plasma. Assay of enzymes of lysosomal origin in plasma, I.

Several lysosomal enzymes present in human plasma (N-acetyl-beta-glucosaminidase, beta-glucuronidase, beta-galactosidase, alpha-galactosidase, alpha-L-fucosidase, alpha-mannosidase, beta-glucosidase) were maintained in a fully active state for at least 8 months by the addition of ethylene glycol (300 milligrams final concentration) to freshly prepared plasma and storage at -20 degrees C. Pools of human plasma from healthy humans, stabilized and stored as above, and containing a low, medium or high content of the above enzymes, were used to establish the analytical imprecision (within-run, day-to-day and total imprecision) of the fluorimetric assay. Ten replicates in ten different analytical series, covering a period of two months, were performed. The total imprecision (expressed as coefficient of variation) was in general lower than 10%; in a few cases, particularly plasma samples with a low enzyme content, the total imprecision was 18%. The isozymes A, B, I1, and I2 of N-acetyl-beta-glucosaminidase displayed the same stability upon storage as the unfractionated enzyme. It is concluded that pools of human plasma containing known amounts of lysosomal enzymes, stabilized by the addition of 300 micrograms ethylene glycol and stored at -20 degrees C, are suitable liquid materials for calibration and quality control for the assay of the same enzymes.

Acetylglucosaminidase↗
PubMed1991

[The prevention of deep venous thrombosis in patients undergoing an internal arteriovenous fistula intervention].

Twenty patients, submitted to internal arteriovenous fistula procedure, were randomly assigned to one of the following treatments: defibrotide 400 mg b.i.d. IM (starting the day before surgery and continuing for the following 7 days); calcium heparin 5,000 IU t.i.d. SC (since the day of surgery and for the following 7 days). No deep venous thrombosis or thrombosis of the fistula were noticed during both treatments and no side effects were observed. In the defibrotide group, ELT showed a significant decrease (-40%) attesting an improvement of fibrinolysis without a plasminogen abatement. These findings indicate that defibrotide represent an effective alternative to calcium heparin for antithrombotic prophylaxis of A-V fistula in uremic patients.

Arteriovenous Shunt, Surgical↗
PubMed1990

Cloning and characterization of the iron-sulfur subunit gene of succinate dehydrogenase from Saccharomyces cerevisiae.

We describe the cloning and characterization of the complete gene for the iron-sulfur protein subunit of succinate dehydrogenase (EC 1.3.99.1) from Saccharomyces cerevisiae. The promoter and coding sequence have been cloned into an Escherichia coli-yeast shuttle vector. The cloned gene complements the defect in a succinate dehydrogenase-deficient yeast mutant isolated by us, and gene expression is fully responsive to induction by glucose deprivation, indicating that the promoter is intact.

Amino Acid Sequence↗
PubMed1979

Optimal conditions for the assay of fibroblast neuraminidase with different natural substrates.

A method for the assay of neuraminidase in human cultured fibroblasts has been worked out. The substrates, all naturally occurring, were: sialyloligosaccharides (alpha(2 lead to 3)sialyllactose, alpha(2 leads to 6)sialyllactose, disialyllactose), sialylglycoplipids (disialogangliosides GD1a and GD1b), sialylglycoproteins and sialylglycopeptides (ovine submaxillary glycoprotein and its pronase-glycopeptides). The method was based on the determination of the enzymically liberated N-acetylneuraminic acid (NeuAc) by a chromatographic-colorimetric microprocedure. The enzyme acted on sialyloligosaccharides and, in the presence of Triton X-100, on gangliosides, while it did not appreciably affect sialylglycoproteins and sialylglycopeptides. The optimum pH was 4.0 for all tested substrates; the Km values were higher for sialyloligosaccharides (about 10(-3) M), lower for gangliosides (about 10(-4) M); the apparent maximum velocity was higher with alpha(2 leads to 3)sialyllactose (400 mU/mg protein); the reaction rate was linear with time for up to 2 h, and with up to 0.6 mg of enzymic protein. The assay method proved to be sufficiently sensitive (3-4 nmol liberated NeuAc), simple, and reproducible (mean activity on pooled fibroblasts with alpha(2 leads to 3)sialyllactose: 400 mU +/- 6 S.E.).

Cells, Cultured↗
PubMed1978

Studies on brain cytosol neuraminidase. II. Extractability, solubility and intraneuronal distribution of the enzyme in pig brain.

The origin and properties of cytosolic neuraminidase (acylneuraminyl hydrolase, EC 3.2.1.18) from pig brain were studied. 1. The brain extracts containing the cytosol derived from neuronal bodies and glial cells carry 0.69 munits neuraminidase/g fresh tissue. The behaviour of neuraminidase during extraction closely paralleled that of authentic cytosolic enzyme, lactate dehydrogenase; whereas, it differed from that of the lysosomal enzymes, beta-hexosaminidase and beta-galactosidase, also found in the extracts. 2. Nerve endings from either crude or purified preparations, when treated by hypoosmotic shock, released neuraminidase activity up to a maximum of 1.25 munits/g fresh tissue. The behaviour of releasable neuraminidase was always identical to that of lactate dehydrogenase and very similar to that of ATPase and acetylcholinesterase. Typical lysosomal enzymes, however, such as beta-galactosidase and beta-hexosaminidase, behaved differently under the same conditions. This neuraminidase activity is thought to be derived from the cytosol of nerve endings. 3. The specific activity of neuraminidase in nerve-ending cytosol is 15--20 times that in neuronal body and glial cell cytosol. Some properties (pH, Km value, V/t relationship) of the cytosolic enzymes of different origin are similar; others (stability on standing at 4 degrees C; resistance to freezing and thawing) are different. Hypoionic solutions caused both cytosolic neuraminidases to slowly precipitate and to assume a stable insoluble form which was still active.

Animals↗
PubMedDate not supplied

Diabetes in the elderly: remarks from an epidemiological study carried out in a town in south-eastern Sicily (Militello V.C.).

Longer mean life span and life expectancy of diabetics and increased factors that favor onset of type II diabetes have determined greater prevalence of diabetes in the elderly population. According to HANES II, it is 17% in the elderly in U.S.A. We carried out an epidemiological study on the over 65 year olds in Militello V.C. and examined 910 elderly subjects (72.05% of the total elderly population). All were tested for peripheral fasting blood glucose, body weight and height and filled out a questionnaire with general and diabetological questions. The values recommended by the NDDG were used to diagnose diabetes. One hundred and sixty-one diabetics (25 newly diagnosed) were observed (17.69%). Onset had occurred before age 65 (aged diabetics) in 72 cases and after 65 in 89 (senile diabetics). Mean blood glucose was 152.91 +/- 55.56 mg/dl. Our results indicated that sulfonylureas and/or biguanides are first choice treatment. By grouping the diabetics on the basis of age at onset and duration of disease, a fall in the number of cases treated with diet alone and hypoglycemic drugs and an increase in patients on insulin were seen in aged diabetics as the disease evolves. On the contrary, there was a rise in the number of senile diabetics on hypoglycemic drugs.

Age Factors↗