Short Communication: Antimicrobial Drug Susceptibility of Staphylococcus aureus from Subclinical Bovine Mastitis in Italy

The antimicrobial susceptibility of 68 Staphylococcus aureus isolates collected during 2004 from milk of cows affected by subclinical mastitis was examined. The antimicrobial agents tested were the beta-lactams, penicillin G, amoxicillin, ampicillin, cloxacillin, amoxicillin + clavulanate, cephalonium, and cefoperazone; and other drugs including lincomycin, oxytetracycline, doxycycline, and kanamycin. Minimum inhibitory concentrations recorded show that only certain beta-lactamase-resistant penicillins (specifically cloxacillin) or penicillin combinations (amoxicillin + clavulanate) were consistently effective against Staph. aureus, whereas the other beta-lactam derivatives and drugs from other pharmacological groups were either moderately effective or ineffective. Thus, beta-lactamase-resistant penicillins are to be considered the antimicrobial agents of choice for treatment of bovine mastitis resulting from infection by Staph. aureus.

Flumequine in the goat: pharmacokinetics after intravenous and intramuscular administration

The pharmacokinetics of flumequine, administered intravenously and intramuscularly at a single dose of 20 mg/kg, was investigated in healthy goats. After intravenous injection, flumequine distributed rapidly (t1/2alpha = 0.87+/-0.15 h) but was eliminated slowly (t1/2beta = 7.12+/-1.27 h); mean clearance (Cl) and volume of distribution (Vdss) were 0.32+/-0.03 (L/(h x kg) and 1.22+/-029 (L/kg), respectively. After intramuscular administration, the peakserum concentration (Cmax = 7.40+/-0.5 microg/ml) was reached in about 1.5 h (Tmax) and bioavailability was about 93%. Estimated flumequine serum levels following repeated intramuscular administration of the aqueous suspension used in the study (7.23+/-0.7 microg/ml and 4.82+/-0.47 microg/ml at intervals of 8 and 12 h, respectively) indicated that to maintain serum levels above MIC values for susceptible bacteria a dosage regimen of 20 mg/kg every 12 h is necessary by the intramuscular route.

Pharmacodynamics and pharmacokinetics of flumequine in pigs after single intravenous and intramuscular administration

The pharmacokinetics and intramuscular (IM) bioavailability of flumequine (15 mgkg(-1)) were investigated in healthy pigs and the findings related to published minimal inhibitory concentrations (MICs) for susceptible bacteria of animal origin, and to experimentally determined MICs for susceptible strains of porcine origin. We found MICs for Escherichia coli, Salmonella spp., Pasteurella spp. and Bordetella spp. in the range 0.5 to >64 microg mL(-1) isolated from infected pigs in the Forli area of Italy; only the Pasteurella multocida strains were sensitive (MIC(90)=0.5 microg mL(-1)). After intravenous (IV) injection, flumequine was slowly distributed and eliminated (t(1/2lambda(1))1.40+/-0.16 h and t(1/2lambda(2))6.35+/-1.69 h). The distribution volume at steady state (V(dss)) was 752.59+/-84.03 mL kg(-1) and clearance (Cl(B)) was 237.19+/-17.88 mL kg(-1)h(-1). After IM administration, peak serum concentration (4.99+/-0.92 microg mL(-1)) was reached between the 2nd and the 3rd hour. The results on MIC of isolated bacteria, although only indicative, suggest that the efficacy of flumequine on Gram-negative bacteria may be impaired by the emergence of less sensitive or resistant strains.

Subclinical Mastitis and Antimicrobial Susceptibility of Staphylococcus caprae and Staphylococcus epidermidis Isolated from Two Italian Goat Herds

A total of 156 goats from 2 commercial dairy goat farms were monitored for intramammary infections during an entire lactation. Most of the infections (80.7%) observed were due to coagulase-negative staphylococci (CNS) species. In herd 1, nearly all of the infections (96%) were due to CNS species, with Staphylococcus caprae (SCAP) being the most common specific pathogen observed, accounting for about 43% of the infections. In herd 2, the proportion of the infections due to CNS was 67% and Staphylococcus epidermidis (SEPI) was the most common pathogen (48% of infections) and SCAP was not present. Linear somatic cell scores (SCS) were greater in milk from infected udder halves, with an average difference of 0.78 SCS. The SCS for infected udder halves was greater than noninfected for all CNS species, although differences among species were observed. The ranking across CNS species was SCAP > other CNS > SEPI > no infection. However, infections by SEPI tended to be more persistent. Increased SCS was associated with a statistically significant decrease in milk yield, but no effect was observed for intramammary infections (IMI). Ninety-seven isolates of CNS (53 SCAP and 44 SEPI) were investigated for in vitro susceptibility to several antimicrobial agents. Benzylpenicillin was the most effective antimicrobial agent against SCAP and SEPI. A concentration of 0.05 microg/mL was sufficient to inhibit growth of 90% of SCAP colonies, and 0.10 microg/mL yielded a similar effectiveness for SEPI. Amoxicillin and the combination of amoxicillin and clavulanic acid were only slightly less effective. Tetracycline (62.5 microg/mL) and tilmicosin (500 microg/mL) were the least effective treatments for SEPI and SCAP, respectively.

Evaluation of the protective effects of alpha-tocopherol and retinol against ochratoxin A cytotoxicity

Ochratoxin A (OTA), a mycotoxin frequently present in food and feedstuffs, produces a wide range of toxic effects, including cell death via lipid peroxidation. In one human and four animal cell lines we determined the half lethal concentration (LC50) of OTA, its effect on reactive oxygen species (ROS) production, and its ability to induce cytochrome p450 activity. We also examined the protective effect of alpha-tocopherol and all-trans-retinol in the most sensitive cell lines (i.e. bovine mammary epithelia, for which LC50 was 0.8 microg/ml (24 h), and Madin Darby canine kidney, for which LC50 was 4.3 microg/ml (48 h)). Pre-incubation for 3 h with either antioxidant significantly (P<0.05) ameliorated the OTA-induced reduction in cell viability and significantly decreased (P<0.05) ROS production. These findings indicate that oxidative stress is an important factor in OTA cytotoxicity. Supplementation with antioxidant molecules may counteract the short-term toxicity of this mycotoxin.

Pharmacodynamics and pharmacokinetics of cefoperazone and cefamandole in dogs following single dose intravenous and intramuscular administration

The pharmacokinetics and intramuscular (i.m.) bioavailability of cefoperazone and cefamandole (20mg/kg) were investigated in dogs and the findings related to minimal inhibitory concentrations (MICs) for 90 bacterial strains isolated clinically from dogs. The MICs of cefamandole for Staphylococcus intermedius (MIC(90) 0.125 microg/mL) were lower than those of cefoperazone (MIC(90) 0.5 micro/mL) although the latter was more effective against Escherichia coli strains (MIC(90) 2.0 microg/mL vs. 4.0 microg/mL). The pharmacokinetics of the drugs after intravenous administrations were similar: a rapid distribution phase was followed by a slower elimination phase (t((1/2)lambda2) 84.0+/-21.3 min for cefoperazone and 81.4+/-9.7 min for cefamandole). The apparent volume of distribution and body clearance were 0.233 L/kg and 1.96 mL/kg/min for cefoperazone, 0.190 L/kg and 1.76 mL/kg/min for cefamandole. After i.m. administration the bioavailability and peak serum concentration of cefamandole (85.1+/-13.5% and 35.9+/-5.4 microg/mL) were significantly higher than cefoperazone (41.4+/-7.1% and 24.5+/-3.0 micog/mL), but not the serum half-lives (t(1/2el) 134.3+/-12.6 min for cefoperazone and 145.4+/-12.3 min for cefamandole). The time above MIC(90) indicated that cefamandole can be administered once daily to dogs for the treatment of staphylococcal infections (T>MIC for S. intermedius 23.8+/-0.3 and for Staphylococcus aureus 21.6+/-0.6h).

Effectiveness and kinetic behaviour of tilmicosin in the treatment of respiratory infections in sheep

Nineteen sheep which were anorexic, pyrexic, coughing, dyspnoeic and had a nasal discharge and symptomatic thoracic sounds on auscultation, received a single subcutaneous dose of 10 mg/kg bodyweight of tilmicosin. The clinical signs were eliminated within four to six days. The kinetic profiles of the drug after a single subcutaneous injection were compared in five healthy sheep and five infected sheep. More of the drug was absorbed by the infected animals and its concentration remained higher for significantly longer. The drug was well tolerated and no local or systemic side effects were observed.

Kinetic behavior of three preparations of alpha-tocopherol after oral administration to postpubertal heifers

OBJECTIVE

To assess the kinetic behavior of 3 preparations of alpha-tocopherol (vitamin E) after oral administration to heifers.

ANIMALS

8 postpubertal Friesian heifers.

PROCEDURE

A single oral bolus of 5,000 U of alpha-tocopherol in oil or encapsulated in liposomes or cyclodextrin was administered to each cow, using a 4 X 4 design with 8 days between treatments. Blood samples for kinetic analyses were obtained at various times for 168 hours after treatment.

RESULTS

Mean (+/- SEM) maximal plasma concentrations of alpha-tocopherol were 4.86 +/- 0.49 microg/ml, 5.03 +/- 0.39 microg/ml, and 5.08 +/- 0.56 microg/ml after administration of oil, liposomal, and cyclodextrin preparations, respectively. Plasma concentrations peaked 21 to 34 hours after administration. The disappearance rate constant (Kd) was less after administration of alpha-tocopherol encapsulated in liposomes, compared with the other 2 preparations. Area under the concentration versus time curve was greater after administration of either encapsulated form of alpha-tocopherol, compared with alpha-tocopherol in oil, but these differences were not significant.

CONCLUSIONS AND CLINICAL RELEVANCE

The lower Kd determined for alpha-tocopherol encapsulated in liposomes suggests that this formulation may result in longer persistance of the vitamin in plasma than the other 2 preparations. Dietary supplementation with alpha-tocopherol encapsulated in liposomes may enhance plasma availability of this vitamin in cattle and could be useful during periods of increased vitamin E requirements, such as parturition and early stages of life.

Absorption kinetics and bioavailability of cephalexin in the dog after oral and intramuscular administration

The pharmacokinetics of cephalexin, a first generation cephalosporin, were investigated in dogs using two formulations marketed for humans, but also often employed by practitioners for pet therapy. Cephalexin was administered to five dogs intravenously and intramuscularly as a sodium salt and by the oral route as a monohydrate. The dosage was always 20 mg/kg of active ingredient. A microbiological assay with Sarcina lutea as the test organism was adopted to measure cephalexin concentrations in serum. The mean residence time (MRT) median values after intravenous (i.v.), intramuscular (i.m.) and oral administration (p.o.) were 86 min, 200 min, and 279 min, respectively. After i.m. and oral dosing the peak serum concentrations (24.2 +/- 1.8 micrograms/mL and 20.3 +/- 1.7 micrograms/mL, respectively) were attained at 90 min in all dogs and bioavailabilities were 63 +/- 10% and 57 +/- 5%, respectively. The time course of the cephalexin serum concentrations after oral administration was best described by a model incorporating saturable absorption kinetics of the Michaelis-Menten type: thus in the gastrointestinal tract of dogs a carrier mediated transport for cephalexin similar to that reported in humans, may exist. The predicted average serum concentrations of cephalexin after repeated i.m. and oral administration indicated that, in order to maintain the therapeutic concentrations, the 20 mg/kg b.w. dosage should be administered every 6-8 h.

Disposition of antimony and aminosidine combination after multiple subcutaneous injections in dogs

The disposition of a combination of antimony (Sbv) (12.8 mg/kg) and aminosidine (AM) (10 mg/kg) in 10 healthy Beagle dogs after multiple subcutaneous injections is described. Sbvplasma concentrations were determined by atomic absorption spectrometry, and AM by ion-pair liquid chromatography, using a fluorimetric detector. Sbvreached Cmaxat 60 min, and for about 1 h plasma levels were homogeneously stabilized between 10.78 and 11.76 microgram/mL; by 12 h, Sbvplasma concentrations were close to the detection limit (0.3 microgram/mL). AM Cmaxvalues were recorded after 1 h (30.6+/-3.11 microgram/mL, mean +/- SD), and plasma levels reached values close to the detection limit (0.15 microgram/mL) between 7 and 8 h after injection. Sbvkinetic parameters did not appear modified by the presence of AM. Moreover, repeated injections of the combination did not modify the kinetic behaviour of the two drugs and did not alter the renal function of the animals. The superimposition analysis of the Sbvdata suggests that a twice daily injection of the metal at a dose of 12.8 mg/kg would be sufficient to maintain inhibitory Sbvconcentrations similar to those recorded in humans.

Relative frequency of functional sympathetic and parasympathetic reinnervation after heart transplantation

Although there is evidence of partial sympathetic reinnervation late after transplantation, little is known about the relative frequency of sympathetic and, in particular, parasympathetic reinnervation. We examined the heart rate response to various maneuvers (standing up, handgrip exercise, phase 2 of Valsalva maneuver for sympathetic function, carotid sinus massage, phase 4 of Valsalva maneuver, and atropine for parasympathetic function) in 65 patients 3 to 110 months after transplantation and in 16 healthy volunteers and defined reinnervation as either one normal (>50% of control group) and at least one partial (>33% of control group) heart rate response or partial responses in all three tests of the respective part of the autonomic nervous system. Thirty-five (54%) patients had sympathetic reinnervation, but only 16 (25%) had parasympathetic reinnervation (p < 0.001); earliest reinnervation was found 11 months after transplantation, and all but one patient with parasympathetic reinnervation also had sympathetic reinnervation. Signs of sympathetic but not parasympathetic reinnervation were common late (>5 years) after transplantation (74% vs 30%).

Relative bioavailability of vitamin E in dairy cows following intraruminal administration of three different preparations of DL-alpha-tocopheryl acetate

DL-alpha-tocopheryl acetate, a synthetic form of vitamin E, is routinely given as a dietary supplement to cattle. In this study we assessed the relative bioavailability of three formulations of DL-alpha-tocopheryl acetate in a kinetic study of plasma alpha-tocopherol in four Italian Friesian dairy cows, following intraruminal administration of a gelatin capsule containing 5,000 IU of DL-alpha-tocopheryl acetate. A Latin square design was used so that each animal received all formulations: (A) adsorbed on silica, (M) microencapsulated and (O) in oil form; 5,000 IU of DL-alpha-tocopheryl acetate was also administered intraperitoneally. The treatments were given following a 2-week period on a diet having no vitamin E supplementation with an interval of 8 days between each administration. Blood samples were collected at 0, 1, 10, 11, 21, 30, 48, 72, 96 and 168 h after each administration. The mean initial plasma alpha-tocopherol concentration (CO) was 2.38 +/- 0.57 micrograms/mL. Maximum plasma concentrations (Cmax) of alpha-tocopherol, adjusted for pretreatment values, were 3.90 +/- 0.13, 3.29 +/- 0.13 and 4.07 +/- 0.19 micrograms/mL, following administration of the A, M and O forms, respectively. The length of time required to obtain the maximum concentration (Tmax) in plasma was 57.5 +/- 7.8, 76.8 +/- 8.9 and 73.1 +/- 14.1 h, and the area under the curve (AUC) was 503.3 +/- 63, 620.25 +/- 108.5 and 465.4 +/- 38.7 micrograms.h/mL for A, M and O forms, respectively. Administration significantly increased the plasma alpha-tocopherol levels in all cases; however the A and M formulations had a lower elimination rate than the O form.

[Hospital admissions, diagnostic and therapeutic procedures of patients with colorectal cancer during 5 years after diagnosis: population-based study]

This research evaluated basic parameters of care, also in the terms of costs. The study examined a sample of colorectal cancer cases incident in 1987 in the population of Florence's municipality, taken from the data base of Tuscany Cancer Registry (RTT). We collected, for 71 patients, all clinical records, for the five follow-up years and evaluated the diagnostic and therapeutic procedures (blood tests, histologic examination, instrumental investigation and surgical intervention) and the duration of all hospitalisations. Besides, on the basis of the diagnostic and therapeutic procedures and of the discharge diagnosis, each hospitalisation was coded following the DRG system and the economic cost of hospital care was analysed. The average number of hospitalisations and the average length of stay for patient in five follow-up years are respectively 1.9 (SD = 1.3) and 41.3 (SD = 25.8); the length of stay resulted highly correlated with the stage of disease. The mean hospital cost per patient (about ItL 18.000.000 overall) was higher in patients with more advanced disease at diagnosis. In the period of study an average 125.9 blood tests (SD = 110.7), 1.2 histologic examinations (SD = 0.9) and 10.3 instrumental investigations (SD = 9.0) were performed for each patient; 61 subjects (86%) were submitted to surgical intervention, of which 4 had a second intervention, and 1 subject was submitted to surgical intervention for liver's metastases.

Intramuscular bioavailability of ketoprofen lysine salt in horses

Lysine salts are often used in human pharmaceuticals to increase the solubility and absorption of acidic drugs when these are administered parenterally. In this study the intramuscular bioavailability of ketoprofen administered as the lysine salt was evaluated in horses (n = 5) treated intravenously and intramuscularly (2.2 mg/kg active substance) in a cross-over study. The absorption rate of ketoprofen administered as the lysine salt was rather low: the mean residence time increased from 31.7 min after IV injection to 128.9 min (after IM injection), and the bioavailability was high (mean 92.4%). The calculated steady state plasma concentrations of ketoprofen during multiple dosage were much higher after intramuscular (0.106 g/ml) than after intravenous (0.066 microgram/ml) administration. Intramuscular injections of the ketoprofen lysine salt can therefore be given to horses, which are particularly prone to develop soft tissue reactions, since use of the lysine salt markedly reduced local irritation at the injection site.

Colorectal, lung, and breast cancer care during the three years following the diagnosis: a population-based study

AIMS

We evaluated a number of basic parameters of care during hospitalization that contribute to the total cost of therapy during the 3 years after the first diagnosis of cancer.

METHODS

The study examined a sample of cases of cancer of the colon-rectum (164 cases), lung (160 cases) and breast (144 cases) diagnosed in 1987, taken from the data base of the Tuscany Cancer Registry. All the information collected by the Registry was examined and the sample was further validated by reviewing original clinical records. The agreement between the two sources was very high, confirming the adequacy of the Registry as a source of information. The parameters evaluated for each patient were the number of cytohistologic examinations, surgery, hospital admissions and days spent in hospital during the 3 follow-up years.

RESULTS

The average number of admittances in 3 years was 1.93 for colorectal, 3.39 for lung and 2.15 for breast cancer. The mean number of days spent in hospital in the 3 follow-up years was 39.9 for colorectal, 50.1 for lung and 21.1 for breast cancer. The parameters differed among subjects still alive, those deceased and those in various stages of the illness.

CONCLUSIONS

The costs of the time spent in hospital, based on the number of days during the first 3 years of the illness, were higher in cases of lung cancer than of the other sites, and more so for patients diagnosed in an advanced phase of the disease.

Pharmacokinetics and dosing regimen of aminosidine in the dog

The kinetic behaviour of the aminoglycoside aminosidine, given at 15 mg/kg intravenously, intramuscularly and subcutaneously, was studied in 5 dogs to determine the appropriate dosage schedule. The pharmacokinetic behaviour of aminosidine in dogs was similar to that in other species, except that it was eliminated more slowly (beta = 0.007 +/- 0.0003 min-1). Intramuscular and subcutaneous administration produced peak serum concentrations (Cmax[im] = 32 +/- 6.4 micrograms/ml; Cmax[ac] = 36 +/- 3.4 micrograms/ml) and times to peak concentration (Tmax = 60 min for both) that did not differ significantly; and neither compartmental nor non-compartmental analysis revealed any significant differences between any of the kinetic parameters obtained for these two extravenous routes of administration. Comparison of these results with previously published data suggests that aminosidine given once daily at 15 mg/kg would be as effective all, and safer than, the two or three daily administrations commonly employed in dogs.

Pharmacokinetics of amoxicillin/clavulanic acid combination after intravenous and oral administration in goats

The intravenous and oral pharmacokinetics of an amoxicillin and clavulanic acid combination (20 mg/kg of sodium amoxicillin and 5 mg/kg of potassium clavulanate) were studied in six goats. After intravenous administration the pharmacokinetics of both drugs could be described by an open two-compartment model. Amoxicillin had a greater distribution volume (0.19 +/- 0.01 l/kg) than clavulanic acid (0.15 +/- 0.01 l/kg), whereas the distribution and elimination constants were higher for the latter, which was eliminated more quickly than amoxicillin. After oral administration of both drugs their pharmacokinetic behaviour was best described by an open one-compartment model with first-order absorption. Elimination half-lives were twice as long after oral (2.15 +/- 0.20 h and 1.94 +/- 0.16 h for amoxicillin and clavulanic acid respectively) than after intravenous administration (1.20 +/- 0.16 h and 0.86 +/- 0.09, respectively). An apparent 'flip-flop' situation was evident in this study. Bioavailability was 27% for amoxicillin and 50% for clavulanic acid.

In vitro comparison of aldicarb oxidation in various food-producing animal species

Aldicarb (ALD) metabolism was studied in vitro using hepatic microsomes from chickens, rabbits, sheep and pigs. The microsomal activities of mono-ooxygenase enzymes (flavin-containing and cytochrome P-450-dependent mixed function oxygenases) were compared by measuring the quantity of the 2 oxidized metabolites, ALD sulfoxide and ALD sulfone, produced during 60 min of incubation. Pig microsomes produced the greatest quantity of ALD sulfoxide and the lowest quantity of ALD sulfone; the latter being produced in greater quantities in sheep than in chickens and rabbits. Aldicarb and its metabolites were degraded fastest in rabbits, probably by hydrolytic reactions. These in vitro results, which are consistent both with the levels of cytochrome P450 found in hepatic microsomes and previous in vivo data on ALD kinetics in pigs, rabbits and chickens, indicate that preliminary in vitro studies can limit the necessary use of animals for drug metabolism experiments.

Disposition of antimony and aminosidine in dogs after administration separately and together: implications for therapy of leishmaniasis

The pharmacokinetic behaviour of aminosidine (15 mg kg-1) and antimony (25.65 mg kg-1 as N-methylglucamine antimoniate), administered subcutaneously either separately or together was studied on four dogs. The results demonstrated that antimony (Sb) did not significantly modify the kinetics of aminosidine (AM) but that the kinetic behaviour of the metal was markedly influenced by the antibiotic, as shown by the differences in mean residence time (MRT), elimination rate constant (Kel) and area under the curve (AUC) with and without the antibiotic (MRT[Sb] = 243.8 +/- 29.5 minutes, MRT[Sb+AM] = 1067.9 +/- 199.2 minutes; Kel[Sb] = 0.008 +/- 0.001 min-1, Kel[Sb+AM] = 0.0015 +/- 0.0003 min-1; AUC[Sb] = 21,024.6 +/- 4448.5 micrograms min ml-1, AUC[Sb+AM] = 130,478.5 +/- 30,481.7 micrograms min ml-1). The persistence of high serum concentrations of antimony when it was administered with aminosidine suggests that the therapeutic doses commonly used should be reduced and that the interval between administration should be increased to avoid the metal reaching toxic concentrations.

Trends in cervical cancer incidence in the district of Florence

The trend in cervical cancer incidence in the District of Florence from 1975 to 1989 was investigated. Tuscany Cancer Registry data were available since 1985. Incidence data from 1975 to 1985 were obtained through a retrospective survey of all the Departments of Pathology and Gynaecology in the district. Cytological screening for cervical cancer has been available in the district since 1973, and since 1980 active invitation of residents aged 25 to 59 years has been in use. A significant trend in decreasing incidence was evident for the overall population (P = 0.003) and for 40-49 (P = 0.028), 50-59 (P < 0.001) and 60-69 (P = 0.002) year age groups, whereas no significant trend was observed for the age group 30-39 years. An association between attendance to screening and reduced incidence was evident, in that a greater reduction was evident for those cohorts (ages 50-59 and 60-69) who had a higher compliance to screening 10-15 years before. If the decrease in cervical cancer incidence was spontaneous, a parallel decrease of CIN3, which is commonly assumed to be the precursor of invasive carcinoma, would be expected. On the contrary, the detection rate of CIN3 at first Pap test showed a significant increase in the study period. All these findings suggest that the observed reduction in cervical cancer incidence was mostly due to the effect of screening, and stress the need for optimising the coverage of the invited population.

Incidence of cutaneous melanoma in the centre of Italy: anatomic site distribution, histologic types and thickness of tumour invasion in a registry-based study

The majority of epidemiological data on cutaneous melanoma (CM) derives from studies carried out in a predominantly fair-skinned population. On the contrary, little is known of the epidemiological figures (including incidence data) in mediterranean populations. The aim of this study was to investigate the incidence rates of CM in a geographically-defined area of the centre of Italy, with particular attention to anatomic site distribution, histologic types and thickness of tumour invasion. After revision of the data base of the Tuscany Cancer Registry concerning the period 1985 to 1987, 282 incident cases of invasive CM (135 males, 147 females) were found in a resident population of 1,174,121 inhabitants. The mean annual age-standardized rates were 6.7/100,000 for males and 7.0/100,000 for females. Site-specific incidence rates showed an almost three-fold higher incidence of CM of the trunk in males than females (3.7/100,000 vs 1.4/100,000). Conversely, a four-fold higher incidence in females than in males was observed for the lesions of lower limb (2.1/100,000 vs 0.5/100,000). A statistically significant difference of incidence rates was also observed for the thigh (females 1.1/100,000, males 0.2/100,000), a normally sun-exposed area. Concerning histologic types of CM, the incidence of the nodular type was higher in males than in females (1.8/100,000 vs 1.3/100,000), even if the difference was not statistically significant in any class of age.(ABSTRACT TRUNCATED AT 250 WORDS)