[Long-term effects on male gonadal function of antitumoral drugs used during childhood]. / Effetti sul sistema riproduttivo maschile dei farmaci antitumorali nei pazienti trattati in età pediatrica.

The survival rate of children and adolescents with cancer has improved dramatically in the last decades so that the prospect of survival in adulthood is today a realistic expectation for about 70% of the treated patients. However, the deleterious impact that chemotherapy and radiotherapy have on the reproductive function and future fertility could compromise the quality of life of the survivors in adulthood. The interest of the scientific community on this topic is increasing and focused on a more accurate evaluation of the reproductive risk among cancer treated children and on the development of less aggressive therapies. In the present review, some information about the long-term effects on the male reproductive function, particularly vulnerable to the cancer therapies, are reported from clinical and experimental studies. Furthermore, the concern about the development of pharmacological treatments and assisted reproductive techniques that might preserve or restore the fertility potential in children being treated with gonadotoxic cancer therapy, is discussed. These new strategies are still under experimentation and deeper knowledges on the functional development of the gonads during infancy, both in human and animals models are required. On the other hand, the future clinical application of these strategies in children rise important ethical and legal problems.

Occupational exposures to metals, solvents and pesticides: recent evidence on male reproductive effects and biological markers.

This review is based primarily on the recent epidemiological studies conducted in occupational settings in order to explore the relationship between exposures to chemical agents and the possible effects on male reproductive function. The paper examines evidence of the effects of metals, solvents, pesticides and dioxin. The effects considered are primarily the possible alterations of sperm quality and reduction of fertility. Many studies have identified small groups of workers with exposures to these agents, presenting some alteration in the spermatological or fertility profile, but the results are difficult to replicate in other settings with different individuals and different levels of exposure. From examination of the concentrations of environmental and occupational pollutants in the blood and in the seminal fluid of exposed individuals, it appears that, in general, the concentrations are much lower in the seminal fluid and in sperm cells, making this a less useful marker of exposure.

[Alkylphenols: assessment of risks for aquatic ecosystems and for human health with particular reference to endocrine effects]. / Alchilfenoli: valutazione dei rischi per gli ecosistemi acquatici e per la salute umana con particolare riferimento agli effetti endocrini.

(Alkylphenols: evaluation of the risk to aquatic ecosystems and human health with reference to endocrine effects).--Endocrine disrupting chemicals (EDC) are a heterogeneous group of substances that can interfere with many endocrine functions. Their effects have been demonstrated in different taxa and they are suspected to affect human health. Alkylphenols are an important group of EDC. They are formed from the degradation of alkylphenol polyethoxylates in the environment or in the sewage treatment plants. They are generally characterized by a high bioconcentration factor (BCF) and accumulate both in sediments and aquatic species. Alkylphenols (APE) show estrogenic activity: studies on fish and rodents put into evidence on both reproductive and developmental effects. In a recent study, the levels of APE detected in seafood from the Adriatic Sea showed a no negligible human health risk for strong fish consumers.

In vivo studies on possible adverse effects on reproduction of the fungicide methyl thiophanate.

The fungicide methyl thiophanate (MT), widely used to control some of the most common fungal diseases in crops, is metabolized in animals into benzimidazole compounds, including the well-known reproductive toxicant carbendazim. However, standard toxicological tests did not indicate that MT may cause testicular toxicity and/or embryotoxicity, which are typical effects of many benzimidazoles. In the present study some aspects of the MT potential for reproductive toxicity have been assayed by means of two non-conventional models. Following the oral administration of 700 and 1000 mg kg(-1) body wt. for five consecutive days, short-term testicular toxicity was examined in the B6C3F1 mouse through specific parameters (sperm head count, specific enzyme activities, histopathology on days 3-35 post-dosing). In spite of the high doses administered, none of the testicular parameters examined, including histopathology, showed significant alterations as compared to controls at any time post-dosing. Pregnant CD rat dams were administered orally the limit dose of 650 mg kg(-1) body wt. day(-1) during preimplantation (gestational day or GD 2-5) or peri-implantation (GD 6-9) phases; embryos and adnexa were evaluated morphologically on GD 12 as a window for the early observation of embryotoxicity. Evident maternal toxicity was present in both treated groups, whereas only marginal reductions of the growth of embryos and adnexa were observed. A full understanding of MT toxicology will need more quantitative data on metabolism, including plasma kinetics and dosimetry of carbendazim at the relevant targets. Nevertheless, the absence of any clear-cut effect on a number of specific endpoints may provide reassurance that no further testing of MT is needed with regard to testicular toxicity or embryotoxicity.

No evidence of effect on male mice germ cells after acute treatment with thiram.

Thiram is a dithiocarbamate compound widely used for industrial processes and agriculture. Animal studies reveal that this compound may affect the male reproductive system. Aim of this study was to test, using sensitive testicular parameters, whether thiram directly affects germinal cells. For this purpose, B6C3F1 mice were intraperitoneally injected with thiram in oil (single dose: 75 mg/kg; repeated five daily doses: 25 mg/kg). Although both treatments were toxic, none of the parameters examined, i.e., testis weight, spermatid head number, specific enzyme levels at different times after treatment (14, 28, 35, 56 days) showed significant variations from the controls. On the contrary, in the positive controls (treated with chlorambucil), a marked reduction of sperm head number as well as a decrease of lactate dehydrogenasex and sorbitol dehydrogenase activity levels were evidenced at day 28, with a tendency to recover at day 35. Under these conditions thiram did not cause cytotoxicity on differentiating spermatogonia and on late spermatocyte stages of mice gonads.

Changes in the levels and forms of rat plasma cholinesterases during chronic diisopropylphosphorofluoridate intoxication.

The effect of chronic administration of diisopropylphosphorofluoridate (DFP) on the levels and forms of plasma cholinesterase (ChE), were studied in male Wistar albino rats sacrificed at different time intervals after various schedules of treatment. In particular the inhibition and recovery rate of the enzymatic activity was evaluated for butyrylcholinesterase (BuChE), determined using butyrylthiocholine (BuThCh) as substrate and for acetylcholinesterase (AChE), measured using acetylthiocholine (AcThCh) in the presence of iso-OMPA 0.1 mM. At 1 1/2 and 24 hr after the DFP treatments, BuChE was considerably more depressed than was the case for AChE. Moreover, the recovery of BuChE proceeded more slowly, its activity being restored only seven days after the last treatment, while the recovery of AChE was completed 72 hr after the end of the treatments. Plasma molecular forms were separated by polyacrylamide gel electrophoresis and were revealed by enzymatic reaction with BuThCh or AcThCh as substrates. By using selective inhibitors, five main molecular forms of BuChE and two of AChE were found to exist in control plasma samples. A differential inhibition and recovery rate was observed among these forms after DFP intoxication. At 1 1/2 hr after the treatments, the BuChE activity was too low to be detected on the gels, but 24 hr thereafter, the quantitative determination of the different forms, performed by scanning densitometry, showed a significant increase of the two faster migrating ones. At the following time intervals, the electrophoretic pattern returned progressively towards normality. The faster migrating forms are therefore probably the first synthesized in the process of recovery of BuChE activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholinesterase molecular forms from rat and human erythrocyte membrane.

1. Some of the biochemical characteristics of acetylcholinesterase from rat and human erythrocytes were studied. 2. Both for rat and man two different acetylcholinesterase molecular forms were identified by gel electrophoresis. The faster moving form is less conspicuous and is not present in all individuals, therefore single-banded and double-banded preparations of red cell acetylcholinesterase can be obtained. The two components appear to be isomers of different molecular size (approximately Mr 150 000 and Mr 245 000) as estimated by gel electrophoresis at different polyacrylamide concentrations. 3. A single band, with a molecular weight of approximately 135 000, was obtained by sodium dodecyl sulphate gel electrophoresis. These results suggest that the faster moving form is a protomer and the slower a dimer. 4. The different sedimentation values obtained by density gradient centrifugation in the presence of Triton X-100 of double-banded (5.3S) and single-banded (6.3S) rat and human acetylcholinesterase preparations, are consistent with a protomer-dimer hypothesis. 5. The isoelectric pattern observed for both double- and single-banded preparations was similar for rat and man acetylcholinesterase and showed a considerable microheterogeneity (thirteen activity bands for rat and eleven for man with isoelectric values from 4.6 to 5.9).

[Comparison between human and rat erythrocyte acetylcholinesterase]. / Confronto tra acetilcolinesterasi eritrocitaria umana e di ratto.

This paper reports on a comparative study of acetylcholinesterase (AChE) extracted from human and rat erythrocytic membranes. The recovery of enzymatic activity when AChE wa solubilized by means of freezing and thawing followed by treatment with 0,5% Triton X-100, represented approximately 95% of the total erythricytic activity for both human and rat preparations. When subjected to gel electrophoresis, the AChE preparation gave rice to two tipes of isoenzimatic patterns: with a single band and two bands (termed band I and band II according to their anodic migration).

A quick and simple method for the routine determination of acetyl- and butyrylcholinesterase in blood.

The salient features of this method for biological monitoring of occupational exposure to organophosphorus insecticides are: (a) acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) are determined separately in whole haemolysed blood using specific substrates at appropriate concentrations; (b) 20 microliter of blood drawn from the finger tip is sufficient for both determinations; (c) the blood sample is immediately diluted with a solution of saponin and may thereafter be frozen for storage; (d) diagnostic kits, commercially available for the determination of plasma BuChE, may be employed with modifications; (e) the kinetic procedure is avoided by blocking the enzyme reactions at the end of the incubation period. This paper describes attempts to achieve optimal conditions for the two reactions. Under the conditions finally chosen, the whole blood 'AChE' activity value still includes a small percentage of plasma BuChE activity (12.5% of the total), while the whole blood 'BuChE' activity includes a small percentage of erythrocyte AChE activity (7% of the total). Results of determinations performed with this procedure on 172 healthy subjects are reported.