Cytogenetic biomonitoring of a floriculturist population in Italy: micronucleus analysis by fluorescence in situ hybridization (FISH) with an all-chromosome centromeric probe

Flower production in greenhouses associated with a heavy use of pesticides is very wide-spread in the western part of the Ligurian region (Italy). The formation of micronuclei in peripheral blood lymphocytes is a valuable cytogenetic biomarker in human populations occupationally exposed to genotoxic compounds. In the present study we investigated the micronucleus frequency in peripheral blood lymphocytes of 52 floriculturists and 24 control subjects by use of the cytokinesis-block methodology associated with fluorescence in situ hybridization with a pan-centromeric probe that allowed to distinguish centromere-positive (C+) and centromere-negative (C-) micronuclei. The comparison between floriculturists and controls did not reveal any statistically significant difference in micronucleus frequency, although an increase was observed with increasing pesticide use, number of genotoxic pesticides used and duration of exposure. An increase in C+ as well as in C- micronuclei and in the percentage of C+ micronuclei with respect to the total number of micronuclei was detected in floriculturists, suggesting a higher contribution of C+ micronuclei in the total number scored. The percentage C+ micronuclei was not related to the duration of exposure or to the number of genotoxic pesticides used, but a higher percentage (66.52% versus 63.78%) was observed in a subgroup of subjects using benzimidazolic compounds, compared with the floriculturist population exposed to a complex pesticide mixture not including benzimidazolics. These results suggest a potential human hazard associated with the exposure to this class of aneuploidy-inducing carcinogens.

Genotoxic action of cycloplatam, a new platinum antitumor drug, on mammalian cells in vivo and in vitro

Cycloplatam (CP), a new antitumor platinum compound of the second generation, was first synthesized in Russia. This drug shows less toxicity in vivo than the widely used cisplatin and carboplatin and a higher antitumor activity than carboplatin. CP is not nephrotoxic with respect to the platinum-based antitumor agents. CP is actually studied in clinical phase II trials in Russia and Armenia. Promising results were obtained in patients with lung, ovary, and prostate cancers. The aim of this work was to study the micronuclei (MN) inducing effect of CP in vivo in murine bone marrow cells and in human lymphocytes in vitro. The mutagenic activity of CP in bone marrow of mice was significantly lower than that of cisplatin at equitoxic doses. In human lymphocytes CP induced a dose-dependent increase of MN, beginning at a very low dose (0.1 micro M). Our results showed that CP is much less toxic and MN inducing in vivo in murine bone marrow than cisplatin. In vitro data evidenced that CP is more toxic and genotoxic to human cells than cisplatin. The evidence of a MN-induced activity of an antitumor drug suggests a potential risk for long-time survivors.

High frequency of micronuclei in peripheral blood lymphocytes as index of susceptibility to pleural malignant mesothelioma

We evaluated the frequency of micronuclei (MN) in peripheral blood lymphocytes of patients with pleural malignant mesotelioma (MM), lung cancer, benign respiratory diseases, and healthy controls. A significant increased frequency of MN was observed in patients with MM in comparison with all the other groups (median, 11.4 binucleated MN/1000 binucleated cells versus 5.1, 6.1, and 6.2, respectively). No association was found between MN and asbestos exposure. Recently, genetic susceptibility associated with asbestos exposure has been recognized in the development of MM. The presence of high frequency of MN in peripheral blood lymphocytes of patients with MM could represent a useful index of individual susceptibility to this tumor.

Micronucleus monitoring of a floriculturist population from western Liguria, Italy

A biomonitoring study was carried out to investigate whether exposure to complex pesticide mixtures in ornamental crop production represents a potential genotoxic risk. Exposed and control subjects were selected in western Liguria (Italy). The area was chosen for its intensive use of pesticides. The main crops produced were roses, mimosas, carnations and chrysanthemums, as ornamental non-edible plants, and tomato, lettuce and basil, as edible ones. The levels of micronuclei (MN) were analysed in peripheral blood lymphocytes of 107 floriculturists (92 men and 15 women) and 61 control subjects (42 men and 19 women). A statistically significant increase in binucleated cells with micronuclei (BNMN) was detected in floriculturists with respect to the control population (4.41 +/- 2.14 MN/1000 cells versus 3.04 +/- 2.14, P < 0.001). The mean number of BNMN varied as a function of sex and age. Smoking habit had no effect on MN frequency. A positive correlation between years of farming and MN frequency in peripheral blood lymphocytes was observed (r = 0.30, P = 0.02). The conditions of exposure were also associated with an increase in cytogenetic damage, with a 28% higher MN frequency in greenhouse workers compared with subjects working only outdoors in fields. Workers not using protective measures during high exposure activities showed an increase in MN frequency. Our findings suggest a potential genotoxic risk due to pesticide exposure.

99mTc HM-PAO brain perfusion SPECT in brain death

Diagnosis of brain death must be certain to allow discontinuation of artificial ventilation and organ transplantation. Brain death is present when all functions of the brain stem have irreversibly ceased. Clinical and electrophysiological criteria may be misinterpreted due to drug intoxication, hypothermia or technical artefacts. Thus, if clinical assessment is suboptimal, reliable early confirmatory tests may be required for demonstrating absence of intracranial blood flow. We have easily carried out and interpreted 99mTc HM-PAO SPECT in a consecutive series of 40 comatose patients with brain damage, without discontinuing therapy. Brain death was diagnosed in 7 patients, by recognising absence of brain perfusion, as shown by no intracranial radionuclide uptake. In patients in whom perfusion was seen on brain scans, HM-PAO SPECT improved assessment of the extent of injury, which in general was larger than suggested by CT.

Cephem sulfones as inactivators of human leukocyte elastase. 5. 7 alpha-Methoxy- and 7 alpha-chloro-1,1-dioxocephem 4-ketones

Studies on cephem sulfones as inhibitors of human leukocyte elastase (HLE) have been extended to the new class of cephem 4-ketones. tert-Butyl and phenyl ketones were prepared from 4-carboxycephem derivatives, at either the sulfide or sulfone oxidation level, by chemoselective Grignard reaction. Obtained products were functionalized with heterocyclothio and acyloxy substituents at C-3', C-2, or both positions. tert-Butyl ketones of the 7 alpha-chlorocephem series were in general at least as potent as the corresponding esters at inhibiting the enzyme, but improvements in hydrolytic stability were only marginal. On the other hand, tert-butyl ketones of the 7 alpha-methoxycephem series combined potent biochemical activity with acceptable hydrolytic stability, thus overstepping the esters, thiolesters, and amides reported previously. In particular, the tert-butyl ketones possessing a heterocyclothio group at C-3' or C-2 were at least as active as the corresponding tert-butyl esters but 1 order of magnitude more stable in physiologic buffers (pH 7.4, 37 degrees C). Introduction of acyloxy groups at C-2 delivered the most potent HLE inhibitors of the cephem class ever reported, with inhibition parameters often outside the determination limits of our standard protocol (second-order rate constant kon > 2,000,000 M-1 s-1; Ki at steady state < 2 nM). Keto-enol tautomerism was found to depress activity and boost hydrolytic stability. Thus, double substitution with heterocyclic thiols produced compounds with diverging properties, according to the extent of enolate formation at the investigated pH (7.4): the weakly acidic tert-butyl ketones (pKa > or = 5.8) proved to be potent inhibitors (kon over 10(4) M-1 s-1) with reasonable hydrolytic stability (t1/2 = 30-75 h), while the phenyl ketones (pKa < 4) were fair inhibitors (kon over 10(3) M-1 s-1; Ki at steady state approximately 50 nM) with hydrolytic half-lives exceeding 1000 h. Selected compounds efficiently inhibited the degradation of insoluble bovine neck elastin by HLE in a concentration-dependent manner. Intracellular HLE of polymorphonuclear leukocytes was in general unaffected; however, a lipophilic cephem sulfone apparently able to inactivate the enzyme in living cells was identified.

Tc-99m HMPAO SPECT in a cerebral gunshot wound

The authors examined regional cerebral blood flow by using Tc-99m HMPAO SPECT studies in a patient who received a gunshot wound to the brain. Although the presence of the retained bullet's fragments adversely affected the quality of CT images and contraindicated MRI studies, the SPECT examination did not have the same constraints and allowed both therapy assessment and prognostic evaluation. The repair of the cortical defect could also be assessed.

Considerations of brain death on a SPECT cerebral perfusion study

Brain death imaging is often a diagnostic challenge. Cerebral angioscintigraphy is extensively used for this analysis, but this test does not allow the perfusion evaluation of the posterior fossa. The authors report a case in which a SPECT study showed persistence of blood flow in infratentorial structures with total absence of cerebral (supratentorial) perfusion. This finding excluded the diagnosis of brain death.

Crossed cerebello-cerebral diaschisis: a SPECT study

A scintigraphic single photon emission computed tomographic (SPECT) evaluation of frontal perfusion alteration was performed in five patients with known cerebellar lesions but with normal supratentorial computed tomographic (CT) or magnetic resonance (MR) scans. A clearly evident asymmetry was found in prefrontal areas in the four subjects with acquired cerebellar damage. The fifth subject, who had congenital left cerebellar hypoplasia, did not show any frontal flow asymmetry. The data support the growing clinical evidence that the cerebellum contributes to the cognitive processes of the frontal lobes and suggest a possible role for SPECT examination in the assessment of functional cognitive impairment in patients with acquired cerebellar lesions.

Synthesis and structure-activity relations in the class of 2-(pyridyl)penems

The isosteric CH----N substitution in the class of 2-arylpenems results in improved antibacterial activity, with retention of the favorable characteristic of stability towards renal dehydropeptidase. High therapeutic efficacy was demonstrated in experimental mice septicemias with the 2-(3-pyridyl) derivative 2b and its orally absorbed acetoxymethyl ester prodrug 4n.

Gastric and esophageal acidity during continuous treatment with H2-antagonists in uncomplicated esophagitis

Twenty-four-hour gastric and esophageal pH were monitored simultaneously in 19 patients with moderate esophagitis before and after a randomized crossover treatment with 40 mg famotidine or 300 mg ranitidine. Gastroesophageal reflux in patients with esophagitis was compared with that in 22 healthy controls. Patients with esophagitis had more esophageal acidity than controls; the percentage of time with esophageal pH less than 4 was significantly greater during a 24-h period (p less than 0.01) both in the upright (p less than 0.01) and in the supine (p less than 0.01) position. In esophagitis patients the percentage of time with pH less than 4 during the total 24-h period correlated closely with acid reflux in the upright (p less than 0.001) and supine (p less than 0.01) position. This indicates that daytime reflux is probably as injurious to the esophagus as nighttime reflux. Famotidine and ranitidine decreased gastric acidity during the entire 24-h period (p less than 0.001) but not during the daytime or early evening. The inhibitory effect lasted slightly longer with famotidine (12 h) than with ranitidine (10 h). Famotidine and ranitidine reduced esophageal acidity during the entire 24-h period (p less than 0.001) and particularly during the nighttime (p less than 0.001) but not during the daytime. Famotidine and ranitidine also did not modify the esophageal acid clearance. Nightly doses of famotidine or ranitidine were ineffective in reducing GER during daytime hours.

Synthesis and antimicrobial spectrum of FCE 22101 and its orally available ester FCE 22891

The most efficient routes for the synthesis of FCE 22101, a penem antibiotic characterized by a carbamoyloxymethyl sidechain at C-2 identical to that of cefuroxime and cefotaxime, and of FCE 22891, its orally absorbed pro-drug, are described. On the basis of in-vitro antimicrobial profile and other characteristics the compounds have been considered worthy of further development.

Cephalosporins. VII. Synthesis and antibacterial activity of new cephalosporins bearing a 2-imino-3-hydroxythiazoline (2-aminothiazole N-oxide) in the C-7 acylamino side chain

Introduction of a hydroxyl group into the thiazole ring nitrogen of cephalosporins belonging to the cefotiam and cefotaxime families gave rise to products, better described by the tautomeric N-oxide form, which proved particularly active against Gram-negative bacteria. Cephems bearing a (Z)-alkoxyimino functionality are of special interest for broadness of spectrum; among them, 7 beta-[(Z)-2-(2-amino-4-thiazolyl-N-oxide)-2 -methoxyiminoacetamido]-3-(tetrazolo-[1,5-b] pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (5c-7, FCE 20635), in other ways similar to cefotaxime, showed useful levels of activity against cephalosporinase-producing strains resistant to the reference drug. Preliminary in vivo studies demonstrated the therapeutic efficacy of the new compound in the treatment of experimental systemic, subcutaneous and urinary tract infections in mice.

Cephalosporins. VI. Synthesis and structure-activity relationships of new 7 beta-[(Z)-2-alkoxyimino-2-(2-aminothiazol-4-yl)acetamido]cephalosporins with a tetraxolopyridazine at the 3-position

The synthesis and in vitro activity of 7 beta-[(Z)-2-alkoxyimino- 2-(2-aminothiazol-4-yl) acetamido]cephalosporins with a tetrazolo[1,5-b]pyridazine at the 3-position are described. These cephalosporins showed excellent activity against Gram-negative bacteria, including beta-lactamase producing strains. The most interesting compound of the series was 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-methoxyimino acetamido] -3-(8-carboxytetrazolo[1,5-b]pyridazin-6-yl)- thiomethyl-3-cephem-4-carboxylic acid (9, FCE 20485) because of its extraordinarily long half-life and marked in vivo activity.