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Biomedical subjects

G Palumbo

Publications and source records attributed to G Palumbo.

At least 109 records · Page 6Linked to original sources
PubMed1991

Heartbeat perception, instructions, and biofeedback in the control of heart rate.

The present study was designed to examine the possibility that individual differences in heartbeat perception and instructions to control heart rate (HR) may influence the acquisition of voluntary control. Good (n = 20) and poor (n = 20) perceivers of cardiac activity were selected on the basis of their performance according to Whitehead et al. (1977) heartbeat discrimination procedure. Measures of state and trait anxiety (the State-Trait Anxiety Inventory Form X-1 and Form X-2) and Tellegen's Absorption Scale (TAS) were used to assess emotionality and absorptive ability. Good and poor heartbeat perceivers (a) were given non-motivating instructions to try to either increase or decrease their heart rate (HR) with, or (b) without the use of HR-feedback, and (c) were given motivating instructions to try to either increase or decrease their HR with, or (d) without HR-feedback. Heart rate, skin conductance (SC), and EMG activity were monitored. Subjects were also requested to indicate the cognitive strategies used during their HR control training. No relationship between heartbeat perception and state-trait anxiety measures was found. The results did not support the idea that individual differences in heartbeat perception are related to individual differences in HR-control. They did indicate, however, that motivating instructions improve the capacity to increase or decrease HR. Subjects were able to voluntarily increase or decrease their HRs with or without a feedback signal. However, more pronounced HR increases were obtained in the feedback as compared with the no-feedback condition. SC and EMG activity were in accordance with arousal levels demanded by HR decrease and increase tasks. Subjects used cognitive strategies concerning activation responses during HR-increase and relaxation responses during HR-decrease conditions.

Adult↗
PubMed1991

Determination of rufloxacin, a new tricyclic fluoroquinolone in biological fluids using high-performance liquid chromatography with ultraviolet detection.

A simple, specific, and sensitive high-performance liquid chromatography method has been developed for routine monitoring of the antimicrobial agent rufloxacin in human serum and urine. Serum or urine-spiked with internal standard pipemidic acid, were vortex-mixed for 2 min with dichloromethane at pH 7.4. The evaporated extract was dissolved in 0.05 M NaOH. The mobile phase consisted of orthophosphoric acid, tetrabutylammonium iodide, and methanol. Drugs were resolved at ambient temperature on a 10 micron Viosfer LC-RP-18 column (250 x 4.6 mm I.D.) equipped with a guard column. Flow rate was 1.8 ml/min, and monitoring was performed at 295 nm. The calibration curve was linear from 0.1 to 10 micrograms/ml for human serum and from 0.05 to 10 micrograms/ml for urine. Retention times were 3.1 and 6.3 min for internal standard and rufloxacin. The detection limit of rufloxacin was 0.05 microgram/ml for human serum and 0.03 microgram/ml for urine. No interference from other commonly administered drugs or endogenous substances was observed. The assay demonstrated sufficient sensitivity and specificity for the study of the pharmacokinetics of rufloxacin in humans.

Anti-Infective Agents↗
PubMed1991

In-vitro and in-vivo activity of roxithromycin against Chlamydia trachomatis.

The object of study was the evaluation of both the in-vitro and in-vivo activity of roxithromycin against Chlamydia trachomatis. In-vitro activity against C. trachomatis was achieved by means of minimum inhibitory concentration (MIC) determinations and was recorded as 0.05 mg/l. In vivo activity was tested in 15 of 60 women, attending the Planning Clinic, who were positive for C. trachomatis. Microbiological diagnosis of chlamydial infection was achieved by using a monoclonal direct smear test (Biomerieux-C trachomatis direct IF). All the patients and their partners were treated with 150 mg of roxithromycin twice a day for 15 days. All the patients were requested to avoid unprotected sexual intercourse up to the end of the therapy. The criterion for clinical efficacy was defined as disappearance of clinical signs and the criterion for microbiological efficacy was evidence of eradication of C. trachomatis at the follow-up (mean time: 30 days). A clinical cure and chlamydial eradication was recorded for all the patients at the end of the treatment and at follow-up. Clinical safety was also satisfactory.

Administration, Oral↗
PubMed1991

[Human low-density lipoproteins are peroxidized by free radicals via chain reactions triggered by the superoxide radical].

Low-density lipoproteins (LDL) oxidized by oxygen radicals (OR) are a potent atherogenic stimulus. Chemically modified LDL are internalized by macrophages via a specific cell surface receptor that was termed the scavenger receptor, and may induce foam cells transformation. A free radical is any chemical species that has an unpaired electron. This property renders it highly chemically reactive. When a radical reacts with a non radical another free radical is generated. This characteristic enables radicals to trigger chain reactions. Oxygen radicals are: superoxide anion (.O2-), hydroxyl radical (.OH) and hydrogen peroxide (H2O2). It is unknown whether LDL are modified via direct lipid oxidation by OR, or whether LDL are subsequently oxidized via chain reactions after initial OR attack. To distinguish between these 2 mechanisms, LDL were exposed to OR formed by xanthine/xanthine oxidase (X/XO). Peroxidation was measured from malonyldialdehyde (MDA) levels. Parallel experiments were performed in presence of the superoxide radical scavenger superoxide dismutase (SOD; 330 U/ml), or the hydrogen peroxide scavenger catalase (CAT; 1000 U/ml), or by adding the chain-reaction inhibitor butylhydroxytoluene (BHT; 1 mM) at selected time points. SOD, but not CAT prevented LDL peroxidation, indicating an obligatory role for superoxide radicals. Superoxide generation in this model lasts only a few minutes, however, MDA levels continued to increase over several hours. Furthermore, this phenomenon was blocked when BHT was added at various times after X/XO. These data show that LDL peroxidation is triggered by initial OR generation but then involves chain reactions which do not require continuous exposure to OR.(ABSTRACT TRUNCATED AT 250 WORDS)

Free Radicals↗
PubMed1991

Some pharmacokinetic data on miocamycin II. Concentrations in gynaecological tissues.

The gynaecological tissue levels of miocamycin were studied in ten female patients after pre-operative administration. The patients were divided into two groups on the basis of the scheduled sampling time. All the patients received 4200 mg of the drug, divided in 7 tablets of 600 mg each every 8 h, last administration 2 or 3 h before surgery. The tissue levels, obtained by means of the microbiological method (Sarcina lutea 9341), were frequently higher than those obtained in the serum at the same time. Miocamycin reached the highest concentration in the endometrium (2.5 micrograms/g) and the lowest in the vagina (1.1-0.8 micrograms/g).

Biological Assay↗
PubMed1990

Structural and ultrastructural study of the ovary in childhood leukemia after successful treatment.

Ovarian biopsy specimens from ten girls (three postmenarcheal) who had undergone antiblastic treatment for acute lymphoblastic leukemia (ALL) and were in complete remission were examined by light microscope. The biopsy specimens from four of these patients (three postmenarcheal) were also observed by electron microscope. The structural and ultrastructural analysis showed a reduction in the number of follicles which were otherwise normal. No follicles were found in the thin sections from two of the three postmenarcheal girls, whereas normal follicles were observed in the third. The cortical stroma showed moderate to severe signs of fibrosis and changes of capillaries. All of these alterations were more evident in patients where ALL was diagnosed at an older age and this finding suggests that they are at a higher risk for low fertility or early menopause.

Acute Disease↗
PubMed1990

The earliest site of iodination in thyroglobulin is residue number 5.

In most highly structured native proteins, as well as in thyroglobulin, the reactivity in vitro of the various tyrosyl residues toward iodine is widely different. The present work demonstrates that of nearly 70 tyrosyl residues present in rat thyroglobulin, there is one, residue number 5 from the NH2-terminal end, which has in vivo the highest affinity toward iodine, being the first one to be iodinated. In fact, when 6-(n-propyl)-2-thiouracil (PTU)-treated, iodine-deficient animals were injected with 125I and killed shortly after, we isolated from thyroid glands poorly iodinated thyroglobulin (about 1 iodine atom/thyroglobulin molecule), nearly 90% of the radioactivity of which was found as monoiodotyrosine. Although CNBr cleavage of this protein gave several fragments after gel electrophoresis only one of these, with apparent mass 27,000 Da, contained 125I. This fragment was isolated and fully characterized. Twelve cycles of automated Edman degradation were performed; the sequence found, i.e. N-I-F-E-X-Q-V-X-A-Q-X-L, indicated that the 27,000-Da fragment is the NH2 terminus of thyroglobulin. This portion of the polypeptide chain contains several tyrosyl residues which may well all be potentially involved in the early iodination of the protein. The observation that the removal of seven amino acids from the NH2 terminus is accompanied (at the fifth step) by the total disappearance of radioactivity in the resulting shortened peptide suggested that the fifth residue was the only one iodinated under these conditions. A second, more quantitative experiment was performed on thyroglobulin obtained from 6-(n-propyl)-2-thiouracil-treated animals whose death was postponed 24 h after the injection of 125I. In this case the radioactivity was found not only in a single CNBr fragment (27,000 Da) but also in other discrete species of lower molecular mass. The mixture of these peptides was subjected to seven steps of manual Edman degradation. Fragments before and after partial degradation were run in parallel on a polyacrylamide gel and the distribution of 125I compared. Besides some change in the background, the two profiles were identical except for the absence of the 27,000-Da species. This proves that all the 125I present in the 27,000-Da species was localized at the fifth residue, the same site at which the hormone molecule is preferentially synthesized under normal conditions. This result is not unexpected and is in accord with the known properties of thyroglobulin which has a polypeptide chain designed for efficient synthesis of the hormone even at low levels of iodination.

Amino Acid Sequence↗
PubMed1990

[Compliance and long-term prognosis in hypertensive patients. Case series in a specialized hospital outpatient service].

In this study of ambulatory patients who had their first visit at the hypertension Unit of the Ospedale San Carlo Borromeo in Milan during the years 1979-1983, we report some data regarding compliance and long-term prognosis of mild hypertension. In these 5 years, 445 mild hypertensives (mean DBP: 103.3 +/- 13.2 mmHg) came to our facilities at least once: of these, 57 (12.9%) have been in constant touch with the outpatient clinic until today; 310 (69.6%) have been lost to follow-up after less than 1 year; 78 (17.5%) had an irregular pattern of attendance with a mean length of follow-up of 3.49 +/- 1.8 years. These data indicate a less than ideal compliance especially for patients who were older, smokers, not married and with no previous pharmacological treatment at the first visit. Index of morbidity and mortality for all causes and for cardiovascular disease and blood pressure control were better, although without reaching statistical significance, in the 57 patients with the best compliance. Altogether our data point to a reevaluation of the approach to the problem of mild hypertension through specialised hospital facilities.

Adult↗
PubMed1990

Several types of adherent cells elaborate a dialyzable lymphopoietic cofactor (Abelson Growth Promoter).

We have cloned a stromal cell from mouse bone marrow selected on the basis of its ability to promote the growth of an Abelson virus-transformed pre-B cell line. These stromal cells have smooth muscle features, and the ultrafiltrate of stromal cell-conditioned medium has proliferative effects on all feeder layer-responsive mouse pre-B cell lines tested, as well as on normal pre-B cells. One of these low MW substances is a protease-resistant factor with an MW of approximately 450 Da which we designate Abelson Growth Promoter (AGP). AGP was initially characterized as an activity which promotes the growth of Abelson virus-transformed mouse pre-B cells, but it also promotes the growth of a ras-transformed pre-B cell line as a single agent and in synergistic fashion with recombinant interleukin (IL) 7. AGP as a single agent has no effect on normal pre-B cells, which have a brisk response to IL-7. In contrast, transformed pre-B cells display a blunted response to IL-7. We propose that AGP plays a role in normal lymphopoiesis by expanding clones of pre-B cells which have been activated by other stromal cell-derived signals, such as IL-7, and directly promotes the growth of nascently transformed pre-B cells.

Abelson murine leukemia virus↗
PubMed1990

Population decentralization within metropolitan areas: 1970-1980.

Using a data set that maintains geographic and fiscal continuity over time and across a sample of major U.S. metropolitan areas, the authors identify factors of economic and population decentralization that affected central city areas between 1970 and 1980. The problems of annexation are resolved by estimating population changes for central cities and suburban areas with constant 1980 boundaries, and by calculating fiscal variables from overlapping jurisdictions by city area as opposed to municipal city government only. "The empirical investigation supports the view that demographic and housing stock variables seem to have had a greater impact on decentralization than central city-suburban fiscal differences."

Americas↗
PubMed1990

Non-steroidal antiinflammatory agents. VII. Synthesis and antiinflammatory activity of 5-methyl-10,11-dihydro-5H-pyrrolo [1,2-b] [1,2,5]benzotriazepine-11-acetic acid and its 10-aroyl derivatives.

The synthesis of 5-methyl-10,11-dihydro-5H-pyrrolo [1,2-b] [1,2,5]benzotriazepine-11-acetic acid and its 10-aroyl derivatives is reported. Compounds were evaluated for antiinflammatory activity by the carrageenin-induced rat paw edema method. Antinociceptic activity was tested by the hot plate and Randall-Selitto tests. General neuropsychopharmacological effects were also screened. All test compounds showed antiinflammatory effect comparable to that of tolmetin.

Analgesics↗
PubMed1990

Research on psychotropic agents. III. Antidepressant activity and neuropsychobehavioural effects of new 5H-Pyrrolo[1,2-b][1,2,5]benzotriazepine derivatives.

The synthesis of 5H-pyrrolo[1,2-b][1,2,5]benzotriazepine derivatives related to imipramine and aptazepine antidepressant agents is reported. Pharmacological screening on new tricyclic derivatives showed that in some cases antidepressant effects at equimolecular dose with imipramine are associated with sedative-muscle relaxant activities and antinociception.

Animals↗