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Biomedical subjects

A Carenzi

Publications and source records attributed to A Carenzi.

At least 37 records · Page 2Linked to original sources
PubMed1984

In vitro antibacterial activity of thiamphenicol.

This in vitro study of thiamphenicol activity against 247 strains of Gram-positive and 195 strains of Gram-negative pathogenic bacteria showed no significant changes from past activity. Of the 442 strains involved, thiamphenicol proved: - Effective (MIC = less than or equal to 0.5-4 micrograms/ml) against 131 strains, mostly streptococci, pneumococci and enterococci. - Moderately effective (MIC = 8-64 micrograms/ml) against 252 strains, mostly staphylococci, Salmonella, Citrobacter, K. pneumoniae, Enterobacter, E. coli and Proteus. - Ineffective (MIC = 64 micrograms/ml) against 59 strains, mostly Proteus, E. coli and K. pneumoniae. Against 23 strains of Neisseria gonorrhoeae, thiamphenicol generally proved as effective as penicillin G and cefuroxime and more effective than spectinomycin.

Bacteria↗
PubMed1983

Effect of inhibition of neuropeptidases on the pain threshold of mice and rats.

The effect of the inhibition of aminopeptidase and enkephalinase A on the pain threshold of mice and rats was investigated, using bestatin and thiorphan as selective peptidase inhibitors. The results indicate that both enzymes are relevant to the catabolism of enkephalins in vivo; however, their simultaneous activation requires particular conditions. These conclusions are based on the following observations: (1) Only concomitant intracerebral treatment with both inhibitors led to an increase in the threshold of animal pain, whereas, in the presence of exogenous peptides, the concomitant injection of both inhibitors in mice elicited an analgesic response greater than the sum of the effects of each single inhibitor. (2) This response could be seen only after acute trauma; in fact, when the drugs were injected through a plastic cannula, only enkephalinase A inhibition was effective in increasing analgesia induced by exogenous peptides.

Aminopeptidases↗
PubMed1976

Regulation of the cyclic guanosine 3'-5' monophosphate system in human brain tumors.

Several reports have suggested that cylcic guanosine 3'-5' monophosphate (cGMP) and cyclic 3'-5' adenosine monophosphate (cAMP) are involved in the regulation of cellular proliferation. Following our previous reports on the cAMP system in human brain tumors, we decided to investigate the cGMP system in the same pathological tissues by studying the activity of guanylate cyclase and cGMP-phosphodiesterase (cGMP-PDE). We found that the activity of both enzymes is lower in neurinomas and glioblastomas than in meningiomas or in normal cerebral cortex. Furthermore, the subcellular distribution of guanylate cyclase in human cerebral cortex differs from that of neurinomas and glioblastomas. On the basis of such observations we have discussed the possibility that the regulatory mechanism of the enzymes related to the cyclic nucleotide metabolism is altered in brain tumors.

Brain Neoplasms↗
PubMed1975

Dopamine-sensitive adenylyl cyclase in human caudate nucleus. A study in control subjects and schizophrenic patients.

Striatal adenylyl cyclase activity from autopsied human brain is selectively stimulated by low concentrations of dopamine. Under the experimental conditions used, norepinephrine was about three times less potent than dopamine. Histamine and serotonin were ineffective. The stimulation by dopamine was competitively inhibited by haloperidol. There was no difference between the basal adenylyl cyclase activity or its level after dopamine stimulation between nine control subjects without a psychiatric history and seven patients with chronic schizophrenia.

Adenosine Triphosphate↗
PubMed1975

Molecular mechanisms in the actions of morphine and viminol (R2) on rat striatum.

Analgesic doses of morphine and viminol R2 increase the turnover rate of dopamine (DA) in rat striatum but fail to increase the striatal concentration of adenosine 3',5'-monophosphate (cAMP) or the affinity of tyrosine hydroxylase (TH) for the pteridine cofactor. When morphine is added to striatal homogenates, it changes neither the basal activity of adenylate cyclase nor the enzyme activation by DA. Similarly to morphine, haloperidol enhances the turnover rate of striatal DA, but unlike morphine it increases the affinity of TH for the pteridine cofactor and blocks the in vitro activation of striatal adenylacte cyclase by DA. Morphine (52 mumol/kg i.p.), viminol R2 (7 mumol/kg i.p.) or haloperidol (2.6 mumol/kg i.p.) fails to increase the striatal cAMP contrations. However (+)-amphetamine (4.8 mumol/kg i.p.) increases DA turnover rate and the striatal cAMP content, but, in doses up to 12.8 mumol/kg i.p., it fails to change the affinity of TH for the pteridine cofactor. This study shows that although (+)-amphetamine, haloperidol and morphine increase the turnover rate of striatal DA each drug possesses a specific profile in its action on molecular mechanisms that control the function of striatal dopaminergic synapses.

Animals↗