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Biomedical subjects

A Marchese

Publications and source records attributed to A Marchese.

At least 91 records · Page 5Linked to original sources
PubMed1993

An Alu sequence interrupts a human 5-hydroxytryptamine1D receptor pseudogene.

Molecular cloning studies have now identified six HTR genes encoding the biosynthesis of the structurally homologous human serotonin (5-hydroxytryptamine; 5-HT) receptors, namely 5-HTR1A, 5-HTR1B, 5-HTR1C, 5-HTR1D, 5-HTR2 and 5-HTRS31. Several of these receptors are encoded by intronless genes, and we now report the cloning of another intronless serotonergic HTR gene. This gene was cloned by a method using the polymerase chain reaction. The nucleotide sequence of this gene is most closely homologous to the 5-HTR1D gene; however, several stop codons, frame shifts and deletions are present in the coding region suggesting that this is a pseudogene which could not encode a functional receptor. Sequence analysis also revealed that the coding sequence of this pseudogene is disrupted by insertion of a 283-bp Alu repeat sequence.

Amino Acid Sequence↗
PubMed1993

Plasmid loss from gram-negative bacteria exposed to subinhibitory concentrations of beta-lactam drugs and azithromycin.

The stability of F'lac, pW101 and pHSG298 in Escherichia coli K12 exposed to subinhibitory concentrations of beta-lactam antibiotics, amikacin and tetracycline was studied. High molecular weight low copy plasmids (F'lac and pW101) were eliminated from bacteria treated with PBP-3 binding molecules, while a low molecular weight high copy extrachromosomal element (pHSG298) was not. None of the carbapenem antibiotics, mecillinam, amikacin or tetracycline promoted high rate plasmid loss from their hosts. Under the same conditions, plasmid-mediated ampicillin-resistance due to beta-lactamase production was also lost from F'lacTn1-carrying bacteria. In contrast, the high copy R6K plasmid was stably inherited in their hosts with the exception of those organisms treated with cefixime. When the same experiments were performed with a Klebsiella pneumoniae strain induced to form filaments by azithromycin at sub-MICs, F'lacTn1 and pW101 loss was detected, while pHSG298 was stably inherited. These results confirm previous observations that plasmid stability is correlated with cell shape and that recovery is more easily achieved when bacteria undergo an unbalanced division resulting in cell filamentation.

Anti-Bacterial Agents↗
PubMed1992

Parameters characterizing the in vitro activity of cefixime, a new oral broad spectrum cephalosporin, against respiratory and urinary pathogens.

The wide and potent in vitro activity of cefixime, a new oral broad spectrum cephalosporin, has been confirmed on a collection of respiratory and urinary pathogens recently isolated in Italy. The new cephem emerged as the most bactericidal of all the comparators tested against several fast as well as slowly-growing gram-negative species including Enterobacteria, Haemophilus and Moraxella, irrespective of their ability to synthetize beta-lactamases. Among the gram-positive species Streptococcus pyogenes and S. pneumoniae were effectively covered. Cefixime activity was not adversely influenced by several important variables such as pH (over the range from 5 to 8), inoculum size (from 10(5) to 10(8) CFU per ml) and the presence of 50% human serum or urine. Time-kill tests confirmed a pronounced bactericidal potency of the drug especially towards common respiratory pathogens (H. influenzae, M. catarrhalis, S. pneumoniae and S. pyogenes). Killing of urinary strains was optimal at cefixime concentrations reached in urine since eradication, except for Proteus mirabilis, was enhanced with increasing levels of the drug. The absence of an untoward paradoxic effect on the rate of cefixime bactericidal action was confirmed by employing a dynamic bladder model simulating the pharmacokinetic parameters of the drug after a single 200 mg daily dosage. Interactions of cefixime with several other drugs that may be employed in combination therapy were generally prone to provide indifference and synergism while antagonism was never observed. Favorable interactions were also registered when cefixime acted with other antibiotics on partially resistant species such as Staphylococci and Pseudomonas. The new cephem seems to provide excellent opportunities for expanding oral cephalosporin therapy to a wide range of infections produced by susceptible pathogens in the adult and pediatric populations.

Anti-Infective Agents, Urinary↗
PubMed1992

Quantitation of HIV viral burden by PCR in HIV seropositive Navy personnel representing Walter Reed stages 1 to 6.

To quantitate the amount of human immunodeficiency virus type 1 (HIV-1) DNA in peripheral blood mononuclear cells (PBMC) of 78 infected individuals, we have developed a polymerase chain reaction (PCR) assay that is both quantitative and sensitive. Quantitation was based on incorporation of a 32P end-labelled primer (SK39) in the PCR reaction and on comparison after electrophoresis with known amounts of HIV DNA. A linear relationship was obtained between the natural logarithms of the radioactive counts detected and the number of HIV-1 DNA copies (10-1000 copies) from the standard DNA. HIV copy numbers from patient samples were then extrapolated from the standard curves. This sensitive and reproducible method was compared with virus isolation which is a semiquantitative evaluation of viral burden. HIV DNA levels correlated with virus isolation, i.e., high viral burden (100-1000 HIV copies) were found in most samples from which virus was isolated after only 7 days in culture; low viral burden (less than 100 HIV copies) was observed in samples from which virus was isolated after 14 to 21 days in culture. These estimates of viral burden were then compared with the clinical stage of the individuals.

DNA, Viral↗
PubMed1992

Ventricular premature beats in young subjects without evidence of cardiac disease: histological findings.

This report describes the results of right ventricle endomyocardial biopsies from 26 subjects (mean age 27 +/- 10 years) with premature ventricular beats and normal cardiac anatomy and mechanical function. Light microscopy examination revealed normal myocardium in 10 subjects (38%), acute myocarditis in two (7%), borderline myocarditis in one (3.5%), non-specific histological abnormalities including cellular hypertrophy, fibrosis and degenerative changes in 11 (42%), vasculitis in one (3.5%) and findings compatible with right ventricular dysplasia in the final subject (3.5%). The frequency of ventricular premature beats, as assessed by Holter monitoring, and the results of electrophysiological testing did not correlate with histopathological findings and their severity. These data indicate that some young subjects with premature ventricular beats of unknown origin have abnormal right ventricular biopsy findings. Adequate follow-up will probably demonstrate the clinical utility of these observations.

Acute Disease↗
PubMed1991

Transcription of a human dopamine D5 pseudogene.

We have previously reported that the human genome contains the two pseudogenes psi DRD5-1, and psi DRD5-2, and that each share 94% homology when compared with the functional gene DRD5. There is only 2% difference at the nucleotide level between the two pseudogenes. We questioned whether these pseudogenes were transcribed, since transcription of either of these pseudogenes could result in false interpretation of in-situ hybridization and Northern blot analysis, using the DRD5 as a probe. We now report that we have detected transcription of one of the pseudogenes, psi DRD5-1, in several human brain areas, and this mRNA transcript is capable of producing a protein of 154 amino acids. Furthermore we report that PCR amplification of DRD5 or the pseudogenes in human tissue can result in the formation of chimer artifacts due to the co-amplification of three very similar genes.

Animals↗
PubMed1991

Arginine8-vasopressin potentiates the motor incoordinating effects of pentobarbital.

Arginine8-vasopressin (AVP, 10 micrograms), injected s.c., potentiated the motor-impairing effects of pentobarbital (10-20 mg/kg) injected i.p. in rats 1 h after AVP. Motor incoordination was assessed on the moving belt task. However, AVP (0.1-100 nM) failed to enhance pentobarbital potentiation of GABA-mediated 36Cl- uptake in rat cerebral cortical or cerebellar microsacs. There was also no effect of a 10 micrograms s.c. injection of AVP 1 h before killing, on pentobarbital potentiation of GABA-mediated chloride flux in either cerebral cortical or cerebellar microsacs.

Animals↗
PubMed1991

Reduction of cat eye movements using retrobulbar botulinum toxin.

We studied the effects of a single retrobulbar injection of Botulinum toxin on the motility of cat eyes. Four cats were sedated and the opposite eye served as a control. Eye movements were plotted by reflecting a laser beam from a mirror fixed to the cornea. We found the mean degrees of deviation per eye per day and summarized these results as mean degrees of deviation per eye per week +/- standard deviation. Statistical analysis was accomplished using Student's t test for independent measures, since measurement of the treated eye pairs was done in a randomized manner on different test days. (table; see text) These results indicate that a single retrobulbar dose of Botulinum toxin can produce a paralysis of the ocular musculature lasting in excess of four weeks in a specific and reproducible manner. In addition, this methodology should prove useful in future experiments in which ocular motility might prove to be a technical concern.

Animals↗
PubMed1990

Doppler continuous-wave analysis of grafted mammary artery as a non-invasive technique for static and dynamic assessment of coronary flow in man.

In this paper, Doppler continuous-wave analysis of blood velocity in the internal mammary artery, anastomosed to the left coronary vascular bed in humans who have undergone myocardial revascularization, is proposed as a non-invasive technique to study coronary blood flow during physiological procedures which cause it to change. Blood velocity curves obtained in normal and anastomosed internal mammary arteries were compared during hyperventilation and the Valsalva manoeuvre. During hyperventilation, blood velocity increased in the normal mammary but not in the anastomosed artery. During the expiratory effort of the Valsalva manoeuvre, the mean blood velocity decreased in the normal mammary artery but it did not change significantly in the anastomosed artery. Variations in the mean velocity were largely prevented by simultaneous and well-balanced increases and decreases in the diastolic and systolic velocities, respectively.

Anastomosis, Surgical↗
PubMed1989

[Doppler velocimetry of the internal mammary artery anastomosed to the anterior descendent coronary artery: a noninvasive analysis of coronary circulation].

This study analyses the static and dynamic characteristics of the flow curves obtained by continuous wave Doppler flow velocity analysis in the internal mammary artery (IM) under normal conditions and after left anterior descending coronary artery by-pass. The IM flow velocity curve has the characteristics of a muscular artery both in basal conditions and during hyperventilation and Valsalva manoeuvre. On the other hand, the by-passed IM shows a typically phasic flow velocity curve, the diastolic flow prevailing over the systolic as is commonly the case in the coronary circulation. This curve also shows variations characteristic of the coronary circulation during Valsalva manoeuvre, whereas it is not affected by the alterations induced by hyperventilation in the area of the respiratory muscles. Continuous wave Doppler flow analysis of the by-passed IM can therefore be considered a reliable method for evaluating coronary flow in man. The fact that this method is non-invasive makes it obviously advantageous and widens its field of application not only to strictly diagnostic evaluations but also to physiopathological and therapeutical ones.

Anastomosis, Surgical↗
PubMed1985

Hereditary macular dystrophies in relation to radionuclide ocular scintigraphy.

Radionuclide ocular scintigraphy was investigated to determine whether it could detect blood-retinal barrier disruption secondary to retinal disease. Patients were examined who had hereditary macular dystrophies and good correlations were found of the dynamic and equilibrium results obtained on scintigraphy with the clinical disease state. This test may hold promise as another measurement of the disruption of ocular physiology in retinal diseases.

Humans↗